Beer, a complete course

Class F1.1

The four ingredients

Almost everything in a glass of beer comes from four things. Once you know which one does what, you can work backwards from a flavour to the decision that caused it.

By the end of this class you will be able to

Name the four ingredients and the job each one does
Work backwards from a flavour in the glass to the ingredient that made it
Explain why hops have nothing to do with how strong a beer is

F1.1.1 The four things in the glass

Four ingredients, four jobs. This is the page to come back to.

Four ingredients. Everything else a brewery adds is a variation on one of these.
Ingredient	What it is	What it gives the beer
Malt	Barley that has been sprouted, then dried in a hot kiln	All the sugar, and therefore all the alcohol. All the colour. Bread, biscuit, caramel, coffee.
Hops	Green cones from a climbing plant, a relative of cannabis	Bitterness, and smell. Grapefruit, pine, mango, grass, pepper. They also keep the beer fresh for longer.
Yeast	A single celled fungus, too small to see	Alcohol and bubbles, plus flavours of its own: banana, pear, clove, pepper.
Water	Most of what is in the glass	How the beer feels in your mouth. The minerals in it can sharpen the bitterness or round out the malt.

Malt is where the alcohol comes from

Yeast can only make alcohol out of sugar, and in beer almost all of the sugar comes from malted barley. So every percentage point of strength traces back to grain. That is worth holding on to, because it is the fact that kills the most common beginner mistake.

Malt also supplies every bit of colour. A pale straw lager and a jet black stout can use the same barley. The difference is how hard the grain was roasted before it ever reached the brewery.

Hops do two separate jobs

Hops give bitterness and hops give smell. Which one you get depends entirely on when they go into the beer. Boiled for an hour, they give bitterness and no smell. Added cold at the end, they give smell and almost no bitterness.

They also work as a preservative, which is why they got into beer in the first place. Before hops, beer went off quickly.

Yeast is not a neutral machine

Yeast eats sugar and produces alcohol and carbon dioxide. It also produces flavour compounds, and they can be loud. The banana in a German wheat beer is yeast. The pepper in a Saison is yeast. No fruit and no spice went into either beer.

Water is not just the liquid part

Roughly 90% to 95% of what is in your glass is water. The dissolved minerals in it change how the beer reads. High sulfate sharpens bitterness and dries the finish. High chloride does the opposite and makes the malt feel rounder and fuller.

This is not a small effect, and brewing history shows it. Burton on Trent in England sits on very high sulfate water, which is part of why English pale ales became crisp and bitter. Pilsen in the Czech Republic has some of the softest water in Europe, which is why the bitterness in a Czech pilsner feels smooth rather than sharp.

Worth remembering

M-H-Y-W. Malt, Hops, Yeast, Water.

Malt brings the sugar, the alcohol and the colour. Hops bring the bitterness and the smell. Yeast brings the bubbles and the fruit. Water brings the feel. Four ingredients, four jobs, always in that order.

Three ingredients, until 1857

The German purity law of 1516 allowed barley, hops and water. Yeast is missing from the list because nobody knew it existed. Brewers just knew that if you kept some of the sediment from a good batch and put it in the next one, the next one worked. Louis Pasteur identified yeast as a living organism in the 1850s.

Check yourself

Pair each ingredient with the job it does.
Answer: Malt with Supplies the sugar, so the alcohol, and all the colour · Hops with Supplies the bitterness and the smell · Yeast with Turns sugar into alcohol, and adds fruit or spice of its own · Water with Sets how sharp or how round the beer feels
Malt is the only real source of sugar, so it is the only real source of alcohol. Hops are seasoning. The pairing people get wrong is yeast, because it is easy to think of it as a neutral machine that only makes alcohol. It is not. In a wheat beer or a Belgian ale the yeast is the loudest thing in the glass.
A beer is 9% alcohol. Which ingredient is responsible for that number?
Answer: Malt, because it supplies nearly all of the sugar the yeast eats
Malt. Yeast is a tempting answer, because yeast is what physically converts sugar into alcohol. But yeast cannot make alcohol out of nothing. A 9% beer is a beer that started with a great deal of grain. Hops add essentially no fermentable sugar at all.
A beer described as very hoppy will be stronger than one described as malty.
Answer: False
False. Hops contribute bitterness and smell, not alcohol. A 4% session IPA can be far more bitter than a 10% barleywine, and the barleywine will be more than twice as strong. The confusion is understandable, because a lot of famous hoppy beers do happen to be strong. That is a habit of American craft brewing, not a rule of chemistry.
Before you read on. The German purity law of 1516 named the only ingredients allowed in beer. How many did it list?
Answer: 3ingredients. You know the modern answer is four. One of the four had not been discovered yet.
Three: barley, hops and water. Yeast is missing because nobody knew it was there. Most people guess four, which is the sensible modern answer and the reason the question is worth asking. Brewers had been using yeast for thousands of years without being able to name it.
Which ingredient is responsible for a beer being pale straw rather than black?
Answer: malt
Malt. Colour comes from how hard the grain was roasted before brewing, and from nothing else. People often guess yeast or water, because both feel mysterious enough to be responsible. Neither has any effect on colour worth mentioning.

F1.1.2 Which ingredient made that flavour

Work backwards. Almost any flavour you notice points at one of the four.

Not a complete list, but it covers most of what a beginner meets.
What you notice	Almost always from	Why
Bread, biscuit, cracker, toast	Malt	Lightly kilned grain. The default flavour of beer with nothing else going on.
Caramel, toffee, raisin	Malt	Grain that was heated while still damp, so the sugars inside caramelised.
Coffee, cocoa, burnt toast	Malt	Grain roasted hard, near 450F. The same reaction that browns bread crust.
Grapefruit, pine, mango, floral	Hops	Aromatic oils, added late or cold so they survive.
A dry, bitter finish	Hops	Bitter compounds, released by a long boil.
Banana, pear, apple, bubblegum	Yeast	Fruity compounds called esters, made during fermentation.
Clove, pepper, a hint of smoke	Yeast	Spicy compounds called phenols. Wanted in a few styles, a fault in most.
A scrubbed, sharp finish	Water	High sulfate. It makes bitterness feel more pointed.
A soft, round, full feel	Water	High chloride. It makes the malt feel fuller.

The last two rows are about feel rather than flavour. Brewers call that mouthfeel, which just means how a beer feels in your mouth rather than how it tastes. Thin, creamy, sharp, sticky, drying. It is often more useful for describing a beer than flavour words are.

The spicy yeast flavours are called phenolic, which is simply the adjective for clove, pepper and that faint medicinal note. In a German wheat beer it is the point of the style. In a pale lager it means something has gone wrong.

Hoppy does not mean strong

This is the single most common wrong assumption a beginner brings to a bar. Hops are a seasoning. They contribute no meaningful sugar, so they contribute no alcohol.

Two beers that make the point. A session IPA at 4.5% can carry 45 IBU of bitterness. An English barleywine at 11% can carry the same. One will end your evening and one will not, and bitterness told you nothing about which.

Try this before the next class

Buy a plain pale lager and a Hefeweizen. Smell both. The lager smells faintly of bread and almost nothing else, because lager yeast is bred to stay quiet. The Hefeweizen smells of banana and clove, and no banana and no clove went into it. That difference is yeast, and you can prove it to yourself for about six dollars.

Covered in Module F2, How beer is made

How malt gets its colour and its flavour. Barley is sprouted, then dried in a kiln. How hot that kiln runs sets both the colour and the flavour, at the same time.

Check yourself

Sort each flavour into the ingredient that produced it.
Answer: Toast and biscuit goes in Malt · Coffee and cocoa goes in Malt · Grapefruit and pine goes in Hops · A dry bitter finish goes in Hops · Banana and bubblegum goes in Yeast · Clove and pepper goes in Yeast
Malt gives the bread and roast flavours, hops give citrus and bitterness, yeast gives fruit and spice. The tempting error is putting banana and clove under hops, because those are also plant smells and hops are the plant everyone has heard of. They come from the yeast working warm, which is why a Hefeweizen tastes of banana and a pale lager does not.
Which of these are genuinely jobs that hops do?
Answer: Make the beer bitter · Make the beer smell of citrus, pine or tropical fruit · Help the beer keep for longer
The first three. Hops bitter the beer, they perfume it, and they slow down spoilage, which is the reason they got into beer in the first place. They add no fermentable sugar, so they cannot raise the alcohol. That last option catches people because strong beers and hoppy beers overlap so often in American craft brewing.
A friend looks at a tap list and says the 70 IBU one will get us drunk fastest. What is the accurate correction?
Answer: IBU is bitterness. Read the ABV instead, because that is the number that decides the evening
Bitterness and strength are set by two different ingredients and two different decisions. IBU measures bitter compounds from the hops. ABV measures alcohol, which came from the malt. The confusion survives because loud, bitter beers are often also strong, so the guess works often enough to feel reliable.
One word for how a beer feels in your mouth rather than how it tastes.
Answer: mouthfeel
Mouthfeel. Thin, creamy, sharp, sticky, drying. It is worth having the word, because feel is often easier to notice than flavour and easier to describe honestly. Saying a beer felt thin is more useful than trying to name six fruits you are not sure you can smell.
The banana smell in a German wheat beer comes from banana or banana flavouring.
Answer: False
False. It comes from the yeast, which produces fruity compounds called esters while it ferments. Brewers get more of them by fermenting warm. It is a reasonable guess, because the smell really is that specific, and plenty of modern beers genuinely do have fruit added. In a traditional Hefeweizen there is nothing in the recipe but grain, hops, water and yeast.

Class 1 done

You can now name the four ingredients, say what each one does, and trace a flavour back to its source.

The three lines worth keeping

M-H-Y-W. Malt, Hops, Yeast, Water.
All the alcohol and all the colour come from the malt.
Hoppy does not mean strong. It never did.

Class F1.2

The three numbers

ABV, IBU and SRM appear on menus everywhere. One of them is reliable, one of them is routinely misread, and one of them causes more bad orders than anything else in beer.

By the end of this class you will be able to

Read ABV off a menu and turn it into how the evening goes
Say what IBU does and does not tell you about how bitter a beer tastes
Break the habit of reading colour as strength

F1.2.1 ABV and IBU

The strength number, which is worth reading every time, and the bitterness number, which is not what most people think it is.

ABV is the one number always worth reading

ABV means alcohol by volume. It is the percentage of the liquid that is pure alcohol. A 5% beer is 5% alcohol and 95% everything else.

ABV	Where you meet it	What it means for the evening
0.0-0.5%	Non alcoholic beer	Legally non alcoholic in the United States below 0.5%
3.5-4.5%	Light lagers, English mild, session beers	You can have three over an evening and be fine
4.5-6.0%	Most lagers, pale ales, stouts, wheat beers	The middle of the road. A pint is roughly one standard drink
6.0-8.0%	IPA, Belgian ales, strong stouts	A pint is closer to two standard drinks
8.0-13%	Double IPA, imperial stout, barleywine	Sipping beers. Often sold in smaller pours for a reason

Worked example: Two pints of a 7.5% IPA

A US standard drink is 14 grams of pure alcohol. That works out as 12 ounces of beer at 5%. Craft beer changes both the pour size and the strength at once, which is why people misjudge it.

The arithmetic: multiply the ounces by the ABV number, then divide by 60.
One 16 ounce pint at 7.5%: 16 times 7.5 is 120.
120 divided by 60 is 2. So that single pint is two standard drinks.
Two pints is four standard drinks, not two.

The same arithmetic on a 12 ounce light lager at 4.2% gives 0.84, so slightly less than one. The gap between those two orders is nearly five to one, and the glasses do not look that different.

IBU is a laboratory number, not a taste

IBU means International Bitterness Units. It counts the bitter compounds dissolved in the beer, measured with an instrument. The scale runs from about 5 to about 100. Most people stop reliably telling the difference somewhere near the top of that range, so a beer advertised at 120 IBU is a marketing number more than a sensory one.

Here is the problem with using it. Sweetness hides bitterness. An imperial stout at 60 IBU can taste sweet and rich. A dry German pils at 35 IBU can taste sharply bitter. The number went one way and your tongue went the other.

Ranges from the BJCP 2021 style guidelines.
Style	IBU	How bitter it actually tastes
American Light Lager	8-12	Not at all
Munich Helles	16-22	Barely. Just enough to balance the malt
German Pils	22-40	Noticeably. Crisp and clean
American IPA	40-70	Yes, and it lasts after you swallow
Imperial Stout	50-90	Much less than the number suggests, because of the sugar

So the useful reading of IBU is a comparison inside a style, not across styles. Two IPAs at 45 and 70 will genuinely differ. An IPA at 45 and a stout at 45 will not taste remotely alike.

Sources disagree

How strong and how bitter is an American IPA?

BJCP 2021, style 21A. 5.5% to 7.5% ABV, 40 to 70 IBU.
Brewers Association 2026, American-Style India Pale Ale. 6.3% to 7.5% ABV, 50 to 70 IBU.

A 5.8% IPA at 45 IBU is inside one document and outside the other. Neither is wrong. The BJCP writes for homebrew competition judges, the Brewers Association writes for commercial competitions, and they draw their lines in different places. Anyone who tells you there is one official answer has only read one of the two.

Sources: What is a standard drink, National Institute on Alcohol Abuse and Alcoholism · BJCP Beer Style Guidelines, 2021 edition · Brewers Association Beer Style Guidelines, 2026 edition

Check yourself

Before you read on. Guinness Draught is the most famous dark beer in the world. Guess its ABV.
Answer: 4.2%. A standard American lager is 5%. Most beers on any bar sit between 4% and 7%.
4.2%, so weaker than a Budweiser. Most people guess high, somewhere near 7%, because it is black and thick looking and the head sits on it like a lid. That guess is the colour trap, and the next slide is entirely about it.
A 16 ounce pour at 7.5%. How many US standard drinks is that? Multiply the ounces by the ABV, then divide by 60.
Answer: 2
Two. 16 times 7.5 is 120, and 120 divided by 60 is 2. People routinely count that as one drink because it arrived in one glass. Counting glasses works fine when every glass is a 12 ounce lager. It stops working the moment the strength and the pour size both move.
A beer with a higher IBU will always taste more bitter than a beer with a lower one.
Answer: False
False. Sweetness masks bitterness, so an imperial stout at 60 IBU often tastes sweeter than a dry pils at 35 IBU. The number is a real measurement of real compounds, which is why it feels trustworthy. What it does not measure is everything else in the beer that is competing with them.
Two beers are both 45 IBU. Which of these would make one of them taste noticeably less bitter than the other?
Answer: A sweeter, fuller malt body · Softer water, with fewer sulfate minerals in it
Sweetness competes with bitterness directly, and low sulfate water makes what bitterness there is feel round rather than sharp. Colour is the tempting wrong answer, because dark beers often do taste less bitter than their IBU suggests. That is the sugar in them talking, not the colour itself. Colour on its own does nothing.
You have an hour and a half and you want to have two or three beers and stay clear headed. Which number on the menu answers that question?
Answer: ABV, because it is the only one that tells you about the alcohol
ABV, every time. It is the one number on a menu that changes what happens to you. IBU tells you about flavour and SRM tells you about colour, and neither has any bearing on how you will feel at the end. Two 4.5% beers and two 9% beers are the same order on paper and a completely different evening.

F1.2.2 SRM and the colour trap

The third number, and the single most common wrong assumption in beer.

SRM measures colour and nothing else

SRM stands for Standard Reference Method. A machine shines light through a sample and measures how much gets absorbed. Low numbers are pale, high numbers are dark. That is the whole of it.

SRM	Looks like	Styles that live there
2-4	Pale straw	American light lager, German pils, Berliner Weisse
5-8	Gold to deep gold	Munich Helles, Kolsch, most hazy IPA
10-16	Amber to copper	American IPA, Vienna lager, amber ale
18-26	Brown	English brown ale, Munich dunkel, doppelbock
30 and up	Black, or near enough	Stout, porter, schwarzbier, black IPA

The trap

People read dark as strong, heavy and bitter. It is none of those things reliably. Colour is set by how far the malt was roasted, and roasting does not add sugar, alcohol, body or bitterness.

Two examples that break the habit. Guinness Draught is 4.2%, which is weaker than a Budweiser at 5%. A West Coast IPA is pale gold and one of the most bitter beers you can buy. Colour predicted both wrong.

It gets worse. A very small amount of very dark grain will turn a whole batch black. So a beer can be jet black and still be built almost entirely from pale malt. Schwarzbier is exactly that: black, and about as light and crisp as a lager gets.

Dark equals heavy

This one survives because it is right in a few very memorable cases. Imperial stouts really are black and strong. Light lagers really are pale and weak. Those two cases stick, and every counterexample gets filed away as an exception.

The replacement is one sentence long. Read the strength, ignore the colour.

What colour genuinely does tell you

It is not useless. A dark beer has had some grain roasted, so you can expect roast flavours: coffee, cocoa, burnt sugar, dark bread. A pale beer has not, so you should not. That is a real prediction and it is usually right. It just says nothing at all about strength, weight or bitterness.

Worth remembering

Colour tells you flavour, not force.

Dark grain means roast flavours. It does not mean alcohol, body or bitterness. Those three come from decisions that have nothing to do with the kiln.

Check yourself

Click the colour band where a German pils sits.
Answer: SRM 2-4
SRM 2 to 5, so the palest band. It is one of the most bitter beers in the German canon and it is also one of the palest, which is the whole point. If you had reached for the amber band because it tastes assertive, that instinct is the colour trap working on you.
Sort these into what SRM tells you and what it does not.
Answer: How dark the beer looks goes in SRM tells you this · Whether to expect roast or coffee flavours goes in SRM tells you this · How strong the beer is goes in SRM tells you nothing about this · How bitter it will taste goes in SRM tells you nothing about this · How heavy it will feel goes in SRM tells you nothing about this
Colour reports one decision: how far the grain was roasted. That does predict roast flavour, which is genuinely useful. It does not predict alcohol, bitterness or body, because those come from the amount of grain, the hops and the mash. Body is the sneakiest of the three, because black beers often do feel thick. Guinness Draught does not.
Someone hands you a jet black beer and says this one will knock you out. What is the accurate response?
Answer: Colour comes from roasted grain, so check the ABV before deciding
Colour and strength are independent decisions. Guinness Draught is black and 4.2%. A Belgian tripel is pale gold and 9%. The belief holds on because imperial stouts exist and are exactly as advertised, so the rule gets confirmed in the most memorable cases and quietly disproved in the boring ones.
A black beer must contain a lot of dark malt.
Answer: False
False. A few percent of very dark grain is enough to turn a whole batch black, so most of the grain in a black beer can still be pale malt. Schwarzbier is built that way and drinks like a crisp lager. The instinct that black means loads of roasted grain is reasonable and simply wrong about the arithmetic.
Write the one sentence replacement for the colour instinct.
Answer: read the strength ignore the colour
Read the strength, ignore the colour. This is the highest value sentence in the module for avoiding an order you regret. Colour reports one decision at the kiln and nothing else. The strength is printed right next to it and answers the question you actually had.

Class 2 done

You can now read all three numbers off a menu and know which of them is worth acting on.

Pocket version

ABV is the only number that changes your evening. Ounces times ABV, divided by 60, gives standard drinks.
IBU compares two beers of the same style and lies about beers of different styles.
Read the strength, ignore the colour.

Class F1.3

Ale and lager

Nearly every beer on earth is one or the other, and the difference is not colour, strength or country. It is which yeast, and how cold.

By the end of this class you will be able to

Say what actually separates an ale from a lager
Predict whether a beer will taste fruity or clean before you order it
Explain why an IPA can smell of mango with no fruit in it

F1.3.1 Two yeast families

One division explains more of what you will taste than any other in beer.

Ale and lager are not two kinds of flavour. They are two kinds of yeast, working at two different temperatures. Everything else follows from that.

	Ale	Lager
Working temperature	60F to 72F, which is 16C to 22C	45F to 55F, which is 7C to 13C
Speed	Days. Often three to seven	Weeks. Two to four, then more cold storage
Flavour from the yeast	Fruit and spice: banana, pear, apple, clove, pepper	Almost none, and that is deliberate
What you taste instead	Yeast, malt and hops all at once	Malt and hops, with nowhere to hide
Typical examples	IPA, stout, wheat beer, most Belgian beer	Pilsner, Helles, Oktoberfest, most beer sold worldwide

Why warm yeast makes fruit

Warm yeast is busy yeast. Alongside alcohol it throws off fruity compounds called esters, and spicy ones called phenols. The warmer the fermentation, the more of both you get.

A Hefeweizen brewer leans into this on purpose, fermenting warm to push the banana and clove up. An IPA brewer usually wants less of it, so the hops stay in front, and ferments at the cool end of the ale range.

Why cold yeast makes nothing

Cold slows the yeast down. It works steadily, produces very little of either compound, and leaves the malt and hops to speak for themselves. That is the entire design goal of a lager.

It also means a lager has nowhere to hide. There is no fruit or spice covering anything, so any fault in the beer is right there in the open. Brewers use pale lager as a test of whether a brewery knows what it is doing.

Worth remembering

Ale is warm and fast. Lager is cold and slow.

Warm and fast gives you fruit and spice from the yeast. Cold and slow gives you a clean beer where the grain and the hops are all you taste. Everything else about the two families comes out of those two words.

What the division is not about

It is not about colour. Schwarzbier and Munich dunkel are black and brown lagers. Belgian tripel is a pale gold ale. It is not about strength either. Doppelbock is a 7% to 10% lager and English mild is a 3% ale. And it is not about country, though Germany and the Czech Republic lean lager and Britain and Belgium lean ale.

Check yourself

Before you read on. Lager yeast works much colder than ale yeast. Guess the temperature a brewer holds a lager at while it ferments.
Answer: 50F. Your fridge runs at about 38F. A traditional British beer cellar is about 55F.
45F to 55F, so right around cellar temperature. Most people guess warmer, because yeast is alive and living things are assumed to want warmth. Cold is the point. It slows the yeast down until it stops producing flavours of its own, which is what makes a lager taste clean.
Sort these into the two families.
Answer: IPA goes in Ale · Stout goes in Ale · Hefeweizen goes in Ale · Pilsner goes in Lager · Munich Helles goes in Lager · Oktoberfest goes in Lager
The dark ones here are the ale side and the pale ones are the lager side, which makes this look like a colour question. It is not, and the next question proves it. Stout is an ale because of the yeast and the temperature, not because it is black. Schwarzbier is just as black and is a lager.
Lager means a pale, light beer and ale means a dark, heavy one.
Answer: False
False. Doppelbock is a lager at 7% to 10%, and Munich dunkel is a brown one. English mild is an ale at about 3%. The habit comes from the beers most people meet first, because the famous lagers are pale and the famous ales are not. The division is about yeast and temperature only.
Why does a Hefeweizen taste of banana while a pale lager tastes of almost nothing but bread?
Answer: The wheat beer was fermented warm, so the yeast produced fruity compounds
Warm fermentation. The yeast makes fruity compounds called esters, and it makes far more of them at 68F than at 50F. Wheat is the tempting answer because the style is named after it, and wheat does change the body and the head. It does not produce banana. Swap the yeast and the banana disappears.
Pair each result with the decision behind it.
Answer: Banana and clove with Fermented an ale yeast warm · Clean, with nothing but malt and hops with Fermented a lager yeast cold · A fault you can spot immediately with Brewed a pale lager, where nothing is hidden · Ready to drink in under a week with Used ale yeast, which works fast
Every one of these traces back to yeast choice and temperature. The last pair catches people out, because ales feel like the more elaborate beers and lagers feel like the mass produced ones. It is the other way round in the brewery. Ale is the quick route and lager takes weeks.

F1.3.2 Why an IPA can taste of fruit

Three separate sources of fruit flavour in beer, and none of them is fruit.

A modern IPA can smell strongly of mango, passionfruit or grapefruit with no fruit anywhere in the recipe. Three different things produce that, and they can all be happening in the same glass.

Fruit you smell	Where it came from	How to tell
Grapefruit, pine, mango, passionfruit	The hops	It hits you before you sip, and it is the first thing to fade as the beer ages
Banana, pear, apple, bubblegum	The yeast, working warm	Strongest in German wheat beer and Belgian beer
Clove, pepper, a faint smokiness	The yeast again, making phenols	Wanted in Hefeweizen and Saison. A fault almost anywhere else
Heavy tropical fruit in a hazy IPA	Both at once	The yeast changes compounds that arrived with the hops

That last row is worth a moment. Some of the strongest smelling compounds in hops arrive locked up and odourless. Yeast can unlock them during fermentation. Brewers call this biotransformation, which just means the yeast chemically altering something that came in with the hops. It is a large part of why a hazy IPA can smell like a fruit stall.

The practical use of all this is prediction. If a beer is fermented warm, expect fruit from the yeast. If it is dry hopped, expect fruit from the hops. If it is a cold fermented lager with a modest hop rate, expect neither, and expect to taste the grain instead.

The beers that break the rule

A handful of styles sit between the two families on purpose.

Kolsch is fermented warm with ale yeast, then stored cold like a lager. It comes out clean with a faint fruitiness.
California Common uses lager yeast at ale temperatures, which is the reverse trick.
Cold IPA is a recent American idea: an IPA fermented with lager yeast to strip out the yeast character and leave only hops.

These are named exceptions, not holes in the rule. The rule is still the most useful single division in beer.

Covered in Module F2, How beer is made

What actually happens during fermentation. Yeast eats sugar and produces alcohol, carbon dioxide, heat and flavour. Temperature decides how much of that last one you get.

Check yourself

A friend smells a hazy IPA and says there must be mango juice in this. What is the accurate correction?
Answer: Hops and yeast can both produce tropical fruit smells with no fruit in the beer
Hop oils smell of tropical fruit on their own, and yeast can unlock more of that smell during fermentation. The guess is fair, because plenty of modern beers genuinely do have fruit added, and a good hazy IPA smells more like mango than mango does. Check the can. If fruit went in, it will say so.
Which of these can produce a fruity smell in a beer with no fruit added?
Answer: Hops added cold, after fermentation · Ale yeast working at the warm end of its range · Yeast altering compounds that arrived with the hops
The first three, and often all three at once. Dark roasted grain is the odd one out: it gives coffee, cocoa and burnt sugar, which is the opposite end of the flavour range. If a beer smells of both roast and tropical fruit, somebody has done that deliberately, and it is probably a black IPA.
What is the word for yeast chemically altering compounds that arrived with the hops?
Answer: biotransformation
Biotransformation. It is worth knowing because it explains why the same hops smell different depending on when they go in and which yeast is working. Fermentation is the tempting answer, and it is not wrong exactly, since this happens during fermentation. It is a specific thing happening inside a larger one.
The clove and pepper notes in a German wheat beer come from spices added to the boil.
Answer: False
False. They come from the yeast, which produces spicy compounds called phenols. A traditional Hefeweizen contains grain, hops, water and yeast and nothing else. Belgian witbier is the beer people are thinking of, because that one genuinely does have coriander and orange peel in it.
Pair each beer with the main source of its fruit or spice character.
Answer: Hefeweizen with Yeast, fermented warm · West Coast IPA with Hops, added late and cold · Hazy IPA with Hops and yeast working together · German pils with Neither. The grain and a clean hop are all there is
Two different mechanisms, and one style where they combine. The pils is included as a control: a cold fermented lager produces almost no yeast character, so what you taste is the grain and the hop and nothing else. If a pils tastes fruity, something has gone wrong with it.

Class 3 done

You can now say what separates an ale from a lager, and predict whether a beer will taste fruity or clean before it arrives.

The line to keep

Ale is warm and fast, and the yeast leaves fingerprints. Lager is cold and slow, and the yeast gets out of the way. Colour, strength and country have nothing to do with it.

Class F1.4

Reading a label or tap list

Every abbreviation a beginner meets on a chalkboard or a can, in one place, with what each one actually changes about the beer in front of you.

By the end of this class you will be able to

Decode any abbreviation on a normal tap list
Know which words in front of a style name change the strength
Choose the right container for taking beer home

F1.4.1 The abbreviations

What each set of letters on a chalkboard stands for, and whether it is worth acting on.

On the menu	Stands for	What it means for you
ABV	Alcohol by volume	The percentage of the liquid that is alcohol. The one number always worth reading.
IBU	International Bitterness Units	A lab measure of bitter compounds. Useful for comparing two beers of the same style, misleading across styles.
SRM	Standard Reference Method	Colour only. Low is pale, high is dark. Says nothing about strength.
OG	Original gravity	How much sugar was in the liquid before the yeast got to it. A brewer number. Usually 1.040 to 1.070.
FG	Final gravity	How much sugar was left afterwards. Usually 1.008 to 1.016. Low means dry, high means sweet and full.
DDH	Double dry hopped	Hopped after fermentation twice, or at double the usual rate. It means a bigger smell. There is no legal definition of it.
NEIPA	New England IPA	The hazy kind. Cloudy, soft, fruity, low bitterness.
DIPA	Double IPA	A stronger IPA, usually 7.5% to 10%. Also written Imperial IPA.
BA	Barrel aged	Rested in a used spirits barrel, usually bourbon. Adds vanilla, coconut and heat, and usually adds strength.
Nitro	Nitrogen pour	Pushed with nitrogen rather than carbon dioxide. Creamy head, softer feel, less fizz. A serving method, not a style.
Cask	Cask conditioned	Finishes fermenting in the container it is poured from. Served cool at 52F to 55F, gently carbonated. A serving method, not a style.

BA is the one genuinely ambiguous entry. On a chalkboard next to a stout it means barrel aged, almost every time. In a written argument about style definitions it means Brewers Association, which is the American trade body that publishes one of the two big style guidelines. Context sorts it out easily.

What OG and FG are for

These two are brewer numbers that occasionally leak onto menus. Gravity means the density of the liquid, which stands in for how much sugar is dissolved in it. Water is 1.000. A beer before fermentation might be 1.055, and 1.012 afterwards.

The gap between them is how much sugar the yeast ate. Brewers call that attenuation, which just means the proportion of the sugar that got fermented. High attenuation gives you a dry, crisp beer. Low attenuation leaves sugar behind and gives you a fuller, sweeter one.

What to actually read

On a busy tap list, read the ABV and the style name. Everything else is either visible in the glass, unreliable across styles, or aimed at brewers. If you only ever read one figure, read the strength.

Check yourself

Pair each abbreviation with what it means.
Answer: DDH with Dry hopped twice, or at double the usual rate · NEIPA with A hazy, soft, low bitterness IPA · DIPA with A stronger IPA, usually 7.5% to 10% · OG with How much sugar was in the liquid before fermentation
The two that get mixed up are DDH and DIPA, because both suggest more of something. DDH is about smell and adds no strength at all. DIPA is about strength. A DDH session IPA at 4.5% is a perfectly normal beer to see on a board.
A chalkboard reads BA Imperial Stout, 13%. What does BA mean here?
Answer: Barrel aged, most likely in a used bourbon barrel
On a tap list next to a strong dark beer, BA means barrel aged. Brewers Association is the other real meaning of those letters, and you will meet it in written arguments about what counts as a style. It never appears on a chalkboard. The 13% is the giveaway, because barrel ageing is nearly always done to strong beer.
Nitro is a style of beer.
Answer: False
False. It is a way of pushing and pouring beer, using nitrogen instead of carbon dioxide. Any beer can go on nitro, though it suits stouts and milds best. The confusion is fair, since the most famous nitro beer in the world is a stout, and a lot of people meet the word and the style together.
Before you read on. A double IPA is a stronger version of a standard IPA. Guess the bottom of its usual strength range.
Answer: 7.5%. A standard American IPA runs 5.5% to 7.5%. Double means the brewer went past the top of that.
7.5% is the floor, and the range runs to about 10%. The word double does not mean twice the alcohol, which is what most people reasonably assume. It means past the top of the normal range, in both strength and hops. Twice the alcohol of a 6% IPA would be 12%, which is barleywine territory.
Which single abbreviation on a menu tells you how your evening is going to go?
Answer: abv
ABV. It is the only one of the three that changes what happens to you rather than what the beer tastes like. IBU is the tempting answer for people who have just learned it, because it feels like insider knowledge. It tells you about flavour, and unreliably at that.

F1.4.2 The words in front, and what it comes in

Words that modify a style name, and the containers you can carry beer home in.

Words that change the style in front of them

Word	What it does	Example
Session	Deliberately weaker than the standard version, so you can have more than one	Session IPA, usually 4% to 5%
Imperial or double	Deliberately stronger than the standard version, and usually louder in every other way too	Imperial stout, 8% to 12%
Adjunct	Made with a sugar source other than malted barley: rice, corn, oats, wheat, honey, plain sugar	Oats in a hazy IPA
Gluten-reduced	Brewed from barley, then treated with an enzyme that breaks up the gluten	Not the same as gluten-free
Gluten-free	Brewed with no barley at all, from sorghum, rice, millet or buckwheat	A genuinely different recipe
Barrel aged	Rested in a used spirits or wine barrel for months	Bourbon barrel aged stout

Adjunct is the one that gets used as an insult, and it does not deserve it. Rice in a Japanese lager, oats in a hazy IPA, wheat in a witbier and lactose in a milk stout are all adjuncts. So is the candi sugar in a Belgian tripel. It simply means a fermentable that is not malted barley.

What it comes in

Container	What it is	How long it lasts
Can	Blocks all light, so the beer cannot be damaged by it. The best format for hoppy beer	Best inside 90 days for an IPA
Bottle	Brown glass blocks most damaging light. Green and clear glass do not	Same, unless it is a strong dark beer
Keg	Sealed, pushed with carbon dioxide, poured through a tap	Weeks once tapped, if the bar is busy
Cask	Living beer, still fermenting, poured without added gas at 52F to 55F	About three days once tapped
Crowler	A 32 ounce can filled and sealed at the bar, to order	Days, because the seal is airtight
Growler	A refillable jug, usually 32 or 64 ounces, filled from the tap	Hours to a day or two once opened

If you are taking beer home, a crowler beats a growler on freshness, because it is sealed like a can and you are not reusing a lid that has been opened fifty times. A growler wins if you already own one and you plan to drink it that evening.

If you are avoiding gluten

Gluten-reduced and gluten-free are not the same thing, and the difference matters medically. A gluten-reduced beer starts as ordinary barley beer and is treated with an enzyme that cuts the gluten proteins into smaller pieces.

United States labelling rules reflect the uncertainty. A beer made from barley may not be labelled gluten-free, even after treatment, and must carry a qualifying statement instead. The standard laboratory test is not considered reliable on beer that has been treated this way, because it looks for pieces the enzyme has already cut up.

If you have coeliac disease, the safe category is beer brewed without barley at all. If you are avoiding gluten by preference, gluten-reduced beer is a reasonable option and tastes much more like normal beer.

Three questions worth asking at a bar

Is anything on nitro tonight. It is usually one tap and rarely advertised.
How fresh is the IPA. A good bar knows, and a hoppy beer past three months is a different drink.
Can I get a half pour of that. Most places do it and almost none advertise it.

Covered in Module F2, How beer is made

Cask, keg, can and nitro in full. Carbonation happens two ways: the yeast makes it, or a tank pushes it in. That choice sets how the beer feels before it ever reaches a glass.

Check yourself

Sort each word by what it does to the strength of the beer it sits in front of.
Answer: Session goes in Weaker than standard · Table goes in Weaker than standard · Light goes in Weaker than standard · Imperial goes in Stronger than standard · Double goes in Stronger than standard
Session, table and light all mean deliberately weaker than usual. Imperial and double both mean deliberately stronger, and brewers use the two words interchangeably. Double is the one that misleads, because it sounds like twice the alcohol. It only means past the top of the normal range.
Someone with coeliac disease asks whether a gluten-reduced IPA is safe for them. What is the honest answer?
Answer: It is not the same as gluten-free, and the usual test is not considered reliable on treated beer
Gluten-reduced beer is barley beer treated with an enzyme, and United States rules will not let it be called gluten-free for that reason. The 20 parts per million answer is tempting because that is the real legal threshold for gluten-free foods. The problem is measurement: the standard test looks for intact pieces that the enzyme has already broken up.
Which of these count as adjuncts?
Answer: Rice · Oats · Lactose, the sugar in milk
An adjunct is any fermentable that is not malted barley, so rice, oats and lactose all qualify. Malted barley is the thing adjuncts are defined against. Lactose is the interesting case, because the yeast cannot ferment it at all, which is exactly why a milk stout stays sweet.
A 32 ounce can, filled and sealed at the bar while you wait. What is it called?
Answer: crowler
A crowler. The growler is the other one: a refillable jug, usually glass, that you bring back. The names are close enough that mixing them up is normal. The practical difference is the seal, which is why a crowler keeps for days and an opened growler does not.
Once filled, a growler keeps as well as a crowler.
Answer: False
False. A crowler is seamed shut like a can, so no air gets in. A growler has a screw cap that has been opened many times and rarely seals as well. Fill a growler on the way to dinner and it is fine. Leave it in the fridge for a week and it will be flat and tasting of wet cardboard.

Module F1 done

You can name the four ingredients, read the three numbers, tell an ale from a lager, and decode a tap list. That is enough to order deliberately rather than hopefully.

What you now know

Malt, hops, yeast, water. Sugar and colour, bitterness and smell, alcohol and fruit, feel.
ABV changes your evening. IBU only compares beers of the same style. SRM is colour alone.
Ale is warm and fast. Lager is cold and slow.
Session down, imperial up, and BA on a chalkboard means barrel aged.