Beer School #6: Beer, Re-Mystified

Last time on Beer School, we learned how beer is a naturally occurring phenomenon, and how yeast are Earth’s version of the great Worms of Dune. It is indeed a miracle of happenstance, what these yeast do, enough to lend years of validity to intelligent design.

It is in fact so wonderful that I hate to do this, but I must. There will be math.

But I offer you this solemn promise: I will do my best to convey the process with all possible clarity, and next to every equation there will be cosplay girls.

Welcome, stalwart travelers, to Beer: Re-Mystified.

There's gonna be math.
Good luck out there…


Now, as we learned in Lesson 5, people don’t make beer. Yeast do. And that process, although as complex and choreographed as a Russian ballet, is as natural as the tides. It requires no human intervention. But there is another process that does require us: and not just human intervention, but human passion, human intellect, and literal eons of accumulated human experience. That of which I speak is the science, and the art, of making beer tasty. Here’s how:

First, choose some yeast. There are basically two kinds, ale and lager. Ale yeast are hardy things. They work quick, and they work best at room temperature (@ 70 degrees F). The flavors they yield are rougher and slightly more assertive. I imagine them wearing Wranglers and hard hats, and sporting Gimli son of Gloin beards. Lager yeast are somewhat snootier. They need to be cool and comfortable before they’ll work (@ 50 degrees F), they work slower, and their flavors are more refined. I imagine them discussing social welfare at gallery openings.

"It's good to be lager."
“It’s good to be lager.”

Next, choose some malt. Malt refers to grain sugars used in brewing. There are basically a jillion kinds, but they’re all barley, roasted to different degrees. The lighter the roast the paler the beer and subtler the flavor. The darker the roast the darker the beer, and the flavors run the gamut from provocatively smoky to burnt cat.

Finally, choose some hops. There are more varieties than you can tell a midget, but there’s no wrong choice. Just remember you want two things out of them, their aroma and their acidity. Choose based on aroma, and note their acid content (always given as a %).

Now, enter your laboratory at the base of the active volcano. Pull the lever that closes the waterfall over the entrance and remove the Kofi Annan mask. Scatter the feral minks. It’s time to brew. And while your five gallons of water are coming to a boil in the cyclops’ skull over the flowing magma, you have time to calculate how much of your hops you want to use.

This is my brewspace. Why? What's yours like?
This is my brewspace. Why? What’s yours like?

Hops contain acid. You want that acid in your beer. So, more hops, right? Sadly, no. The path to greatness is never that easy. It turns out that hops yield up acid to the boiling water as a function of time. In other words, there are three dimensions here: the amount of hops, the amount of acid in the hops, and the amount of time they are allowed to boil. And coaxing a number out of that snake pit, I’m afraid, involves calculations.

First, convert your hops to Home Bittering Units (HBUs). HBUs are defined as the acid contained in 1 ounce of 1% hops.

Just a spoonful of sugar...
Just a spoonful of sugar…

ounces x acid percentage = HBUs

So, for 2 ounces of 15% hops, you get:

2 x 15 = 30 HBU

There. Not so bad. Next, we factor in the time by using this rule of thumb: hops give up 10% of their HBUs after five minutes in the boil, 21% after 30 minutes, and 30% after an hour. This will convert HBUs to AAUs (alpha acid units)

(Amount of hops x HBU)(% by time) = AAUs

So, if you add half the hops at the beginning of an hour’s boil, and the other half five minutes before it’s over, you have two equations to solve. (Why would anyone do this? To add aroma. The longer they’re boiled, the less aroma hops give the beer)

...makes the medicine go down
…makes the medicine go down…

(.5 x 30) x .30 = 4.5 AAU

(.5 x 30) x .10 = 1.5 AAU

Add those two numbers together to get the amount of acid you’ve just added. In this case, it’s six, six, SIX AAUs! Ah ha ha ha! Now, divide that number by the number of gallons you’re making (in this case 5) to get the AAUs per gallon.

AAUs/gallons = AAUs per gallon

6 AAU/5 gallons = 1.2 AAUs per gallon.

Finally, take your AAUs per gallon and divide it by .01335. Why? I’ll tell you why: to convert it to International Bittering Units (IBUs). Okay, but why learn IBUs? Well, so you know, that’s why. And so if a beer snob ever starts talking about them, you can meet him point for point before shoving a clove of garlic in his mouth and spritzing him with holy water. Knowledge is power!

... in the most delightful way
… in the most delightful way

AAUs per gallon/.01335 = IBUs

1.2/.01335 = 89.9 IBUs

So what does that mean? Is that high? Is that low? Hey, I don’t know, Jack. How much malt did you use? What kind? How long are you fermenting it? What flavorants are you adding? See, making beer taste good is an art. There’s a lot of practice and experimentation, and there are no rules except those you impose. All these calculations do is allow you to keep track of what you’ve done so you can re-create it, avoid it, or riff on it like smooth jazz.

Freedom! Innovation! Self-expression! Mmmm, smooth jazz.

And for the record, yeah, 89.9 IBUs is kind of high.

Okay. The math is over. Add your hops and your malt and let that magical elixir boil for an hour. Then cool it down, grab your yeast, and wait a second. You’ll want to savor this moment.

I mean, look at that container of yeast in your hand. Odds are it contains tens of millions, maybe hundreds of millions, of little critters. Now look at that big cauldron of sugar water you just made. Yeast love that stuff. Think about it: when’s the last time you had the opportunity to make hundreds of millions of living creatures ecstatically happy, just with a flick of your wrist? With that in mind, empty the container into your nascent beer. There. Wasn’t that magnificent? You are a hero to an entire microcosm. Put your ear up close, and I swear you can hear them cheering.


Now find some place to stash your container. It needs to be temperature-appropriate for the yeast you used, and it needs to be relatively sheltered. And the container itself needs to have a valve on it somewhere, even a crude one, to let the carbon dioxide out and prevent contaminants. Now walk away.

Ale will typically take about a week. Lager takes longer, Leroy. How much longer? I don’t know. Try it and see. In the meantime get your bottles or keg ready by sanitizing them with anything other than soap (iodine, bleach, boiling, autoclave, cleansing fire) and make sure to leave no residue. Soap and residue kill bubbles.

When you go to bottle the stuff, add some booster sugar for the yeast to munch on. How much of what kind? Again, I don’t know. How carbonated do you want it? You’re the brewer, make some mistakes. Just don’t use maltose.

Bottle or keg your creation and give it another week or two to build up some carbonation before you put it in a refrigerator. Keep it in the fridge for yet another week or two. If you’re making a lager, refrigerate it until the beer clears. It’ll be awesome: the beer is cloudy and ugly for a week or two, but wait long enough and, almost overnight, it becomes sparkling clear. It’s personally validating. You will feel more effective and desirable once your beer turns clear.

This man's beer is clear.
This man’s beer is clear.

Danger! Danger! Do not leave your beer unrefrigerated! Unlike mass-produced beer, which is pasteurized, yours contains live yeast cultures. Leave it unrefrigerated and those yeast will gleefully continue eating sugar and farting carbon dioxide until bottles start going off like unexploded ordnance.

You are done now. Beer accomplished. Plus three experience and charisma.

Your first batch will be delicious. It always is, because you made it. The second will be good, but you will feel as if you lost something ineffable, a certain magical spontaneity, that was present in the first. The third and fourth and subsequent batches will seem worse and worse. Things will go wrong. Fermentation will be sluggish. Carbonation will be flat, then comically intense. Hop profiles will seem uninteresting. Nobody else will notice any damn difference.

But worry not. This is the experimental phase. Try goose-loony stuff. Do everything backwards. Put Viagra in it. Use wheat, rice, and Cheerios. Talk like a pirate. Spice it with your tears. I mean, people drink coffee made from beans picked out of Sumatran cat turds. Nobody knew it was good until some pervert tried it. That pervert could be you!

I crap excellence.
You keep taking my poop. What don’t I know?

This has been by far the longest of the lessons, but it was necessary. Nothing deepens your appreciation of beer like handling the raw ingredients and observing its creation. It’s a surprisingly simple process, but carrying it from component elements to finished potable is, I think, the only way to truly understand the choices made and variables controlled that are evident in every glass.


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