Reader Question: Beer Recipe Formulation

Off-week bonus post!  A while back I got a reader question in response to my article on How to Build a Beer Recipe.  In a nutshell, Mark was a little fuzzy on how much of each ingredient to actually use, something I glossed over in my more conceptual treatment of recipe building.  I thought I would share my response here:

Hi Mark,

I kind of glossed over that part on purpose, as that post was meant to be more conceptual than nuts-and-bolts of brewing, so don’t feel like you’ve missed something.  When you start putting together your own recipes, brewing software or online calculators can really help streamline the process, but its good that you asked first to find out what they are doing instead of just trusting them.  Beyond that, I would definitely recommend picking up a copy of Palmer’s How to Brew, 3rd ed. if you don’t have one (full first edition is online on his webpage also).  In most cases you can more or less follow through the process and get good beers, but you’ll eventually want to pick up some of the science of the mash process so you can diagnose problems and push the envelope.

Hopefully this can at least get you started:

Grain:
First off, you should decide what gravity you are shooting for. Then you’ll need to make some assumptions about how much sugar you can get out of your grain.  This will require knowing how much sugar is in the grain (yield), and how much sugar you can actually pull out of the grain (brew house efficiency).

Table sugar contributes about 46 gravity points per pound per gallon (ppg)/ 386.5 points per kilo per liter (pkgL), so if you put 1 lb of sugar in a pot and enough water to get to one gallon, your hydrometer will read 1.046. Grains have a specified yield based on this (which can be found on the maltster’s spec sheet for the grain).  Most base malts have a yield of about 80%, so one pound of grain can give you at most 46*0.8=36.8 ppg/ 309 pkgL.  Other malts can be much lower (rye is about 60-65%, crystal 70-75%, black patent 55%, etc).

However, its basically impossible to achieve full extraction (and it would make awful beer if you did).  Thus, you also have to take into account your personal brew house efficiency.  There are a ton of factors which can alter this, so its something you will need to dial in on your own.  But, if you are batch sparging like me, you can probably safely assume between 60 and 70% (I would start with 65% and then dial it in from there- keep good notes!).  Thus, a single pound of base malt will actually contribute 46*0.8*0.65=23.9 ppg/ 201 pkgL at 65% brew house efficiency.

So lets look at an example batch.  Lets assume you want a moderate gravity ale, say 1.060, and you think you can get about 65% efficiency, and you are brewing 5 gallons/ 18.9 L (of course you need more than five gallons of water to account for boil off, etc, so the 1.060 target is post boil).  So, you want a total addition of 60*5=300 gravity points (OG = 60, 5 gal batch).  If you were to use all base malt with 80% yield (so 23.9 ppg), you need 300/23.9 = 12.55 lb/ 5.96 kg of grain.  You can of course replace some of this with specialty malts, you just need to account for the different yield of different grains, and keep the total specialty malt amount below about 15% by weight as a general rule (there are of course exceptions!).

Hops:
Hops are a bit trickier to calculate by hand (it can be done, and many sources like How to Brew will show you how, but you should just use an online IBU calculator or one built into another program).  Basically, hops with higher alpha acids will give you more IBUs, as will hops that are boiled longer, up to 60-90 min, at which point it pretty much levels out.  A more concentrated wort will lower your IBU yield for a given amount of hops.  In a 1.060 beer, 1 oz/ 28 g of 13% alpha acid simcoe will contribute about 43 IBUs when boiled for 60 min, but only about 16 IBUs when boiled for 10 min, for example (using the Tinseth approximation).

Yeast:
The general rule of thumb for an ale is that you’ll want 1 million viable yeast cells per milliliter of wort per degree plato (double that for a lager).  And I trust this is just as useless to you as it is to me. Look up the Mr. Malty yeast pitch calculator and you can punch in your gravity and volume, and it will tell you how many packets or vials of yeast to use, or how large of a starter to use.

Water:
This will vary depending on your mashing technique and other factors unique to your set-up.  But generally you want to account for boil off (usually about 1 gallon/ 3.8 L per hour) and the amount absorbed by the grain (usually about 0.5-0.8 quarts of water per pound of grain used or 1-1.6 L/kg), and any other losses in equipment (unable to drain from your MLT, for example).  I have measured my system at 0.9 gallons per hour boil off, 0.55 qrt/lb grain loss, and 0.1 gal equipment loss.  Using these values I can calculate how much water I need to use to get 5 gallons after boiling.  Again, its a must to keep good notes to dial this in.  It usually takes at least 3 batches with great notes and lots of measuring to really nail down the amounts.  I use the water calculator on brewblogger.net for these calculations.

Hopefully that covers at least most of what you were wondering about.  Feel free to write back with any other questions, or anything specific I missed or didn’t explain well.

Do you have a question?  Email me at dennis.lifefermented [at] gmail.com, or use the contact form on the About/ Contact page.  I’ll email you back ASAP, then maybe use it as a bonus post.

– Dennis,
Life, Fermented

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