calculating grain bill

[davidmeyers]

I am trying to calculate my first grain bill. Every resource I have expresses things in gravity units, or on fancy charts. I was hoping somebody could take me through the process so that I might actually understand what it is I am doing with respect to Bbl and plato. Everytime I crunch my numbers, I have no way of knowing if they are correct, and they seem way off.
To keep things simple, let's assume brewhouse eff. is 85%. Volume before the boil is 4Bbl, after is 3.5Bbl, and I want to use 60% 2 row, and 40% malted wheat. We can even use ficticious numbers for the extract yields on the malt, I don't care! I just want to see this done correctly by somebody else. Ok, we can also assume the O.G. to be 12 Plato to finish out at 3.
If you prefer to use different numbers, that's fine too! I read Noonan, Daniels, and Fix, and all 3 seem to have me going around in circles with charts, and homebrewing units. If you don't have the time to take me through the process, if you can offer a link, or another site that can provide this information, I would apperciate it! Whoever does decide to provide this information, would be doing a great service to anyone else who might visit this site, and could use a refresher course, or has just been afraid to ask how to do it. Thank you.

[GlacierBrewing]

Check out http://www.promash.com/. Great program, wonderful tool! (Unlike myself, I'm just an ordinary tool!)
Luck to ya'
Dave

[davidmeyers]

Interesting you should suggest that. We have promash, and use it from time to time. I would just like to know how to do this on paper with a calculator (like they did in the "old days"). I can calculate hop bitterness and isomerization, malt SRM, strike temps, but I can't get the stinkin' malt bill figured out. Without that, the rest is pretty much useless! Thanks for the advice, though. It is a great program.

[Woolsocks]

I think it's excellent that there's someone else out there not relying on the software to do this. That said, I'd recommend the software as a time saver, but not as a crutch.

I find it much easier to do this if you express the extract potential of the malt as % of the total weight rather than this weird "gravity points" notion. Second, it's much easier in metric, so I'll do it that way for the demo purposes.

You want to end with 3.5bbl = 4.1 hL = 410L

First, choose your original gravity -- 12ºP. That means that your wort will be 12% extract by weight. Also, it means that the specfic gravity will be 1.048, so 4.1 hL will weigh 429.7 kg. If it's 12% extract, that means you need 51.6 kg of extract from your grains.

Let's say the extract potential of your grain is 80%, meaning that if you had 100% mash/lauter efficiency, you'd end up with .8 kg of extract for each kg of grain. If your efficiency is actually 85%, then you'd get .68 kg of extract for each kg of grain. So.... to see how much grain you need for your recipe, divide the amount of extract (51.6kg) by the % of the grain you expect to collect as extract (.68) and you get 76.9 kg.

So if it's 60% 2-row, you need 76.9*.6=46.14 kg of 2-row and if it's 40% wheat, you need 76.9*.4=30.76 kg of wheat.

[mr.jay]

I, too admire your desire to learn the "old way." My method is a little different then Woolsocks, but I am sure we arrive at the same conclusion. I actually have an old brewers report with all of the steps (it was from the first time I calculated my grain bill) written out. I copied Oxford's formulas, and crossed referenced them with New Brewing Lager Beer. It accounts for moisture content, FG or CG etc. Email me your fax number, and I can send you a copy.
I would be interested to see some other brewer's methods of determining their malt bill, and the accuracy that they arrive at. My method has a .5 degree margin of error. Most of the time, I am within 1/10 of a degree, but that's based on many variables. If anybody has the patience and time to post their formula, I would also be interested to see how far some of you take it, and how close you come to hitting your targets. As craft brewers, we have a little more room for error, but those guys who need ABSOLUTE consistency, might go a bit further. Where do most of you stand?

[Woolsocks]

Yeah, I should have mentioned that you need to adjust the extract potential of your grains to adjust for moisture content.

Also, I'm wondering; when you say "60% 2-row" for example, does that mean 60% of the grain is 2-row or does it mean 60% of the extract in your kettle is FROM 2-row? A minor point, but one I'm sure the big guys worry about.

[davidmeyers]

60% of the grain bill is pale. Another example would be 10% chocolate malt for a stout, etc.. As I said, anything would be ok to provide an example. Thanks, Woolsocks for your input. I still like to think in terms of pounds and gallons, but I think I am starting to understand how to do this. Mr. Jay, I have sent you an email with my fax number. Thank you!

[Woolsocks]

Well, if you do it as pounds and gallons, you just have to account for the weight of a gallon of water (8.3 lb) or a barrel (258 lb) so 1 barrel of 1.050 beer weighs 271 pounds. This is why I like metric...

[davidmeyers]

Sorry, Mr. Jay, but at this stage, it's way above my head. Thanks anyway, though. When I get better at determining my malt bill, I will try to understand what you sent me.

Mr. Woolsocks, I almost got it! I am a bit confused by how you arrived at the weight of the Bbl after the extract, and how that plays into the equasion. I tried to do the equasion, but it seemed inconclusive, so, if I may (and I would be forever in your debt for your help) ask you to go through this again, with more numbers, and less text.
Heres an example:

60% of the malt bill is 2 row, which has an 80% extraction potential (like you said)
40% of the malt bill is wheat. For all intents and purposes, let's say it's extraction potential is 78%, to add a different figure to the equasion.
brewhouse efficiency is 85% (I understand that, I multiply .8 by .85)
I start with 4 Bbl and boil down to 3.5 Bbl (if that even matters)
O.G. is 12 degrees plato.

I do agree, when I looked over everything, metric is a HECK of a lot easier!
Thank you exponentially in advance. You are a lifesaver!

[Woolsocks]

12ºP = 12% extract by weight
12ºP = 1.048 SG
3.5 bbls of water (SG 1.000) weighs 900 lb
3.5 bbls of 1.048 SG wort weighs 943 lb (900 * 1.048)
Your final boiled wort should weigh 943 lb
12% of that weight should be extract
You need 113 lb of extract in 3.5 bbl wort to hit your target OG

113 lb * .6 = 68 lb, so need to get 68 lb of extract from 2row
113 lb * .4 = 45 lb, so need to get 45 lb of extract from wheat

2row efficiency: .8 *.85 = .68
For every lb of 2row you get .68 lb of 2row extract
68 lb /.68 = 100 lb

Wheat efficiency: .78 *.85 = .66
For every lb of wheat you get .66 lb of wheat extract
45 lb /.66 = 68 lb

So you malt bill should be:
100 lb 2row
68 lb wheat

Pre-boil volume is irrelevant to this because you're concerned only with getting the correct OG on your finished wort, not your preboil wort.

Cool?

[Butcher Scott]

Great thread! Thanks for some really good info on doing calculations, Woolsocks... this is going to help me tremendously in my homebrewing!

[davidmeyers]

:d Eureka! I've Got It! Thank You! I Owe You A Beer! :d :d :d

[big_al]

Calculating Malt bill - metric version

at the risk of repeating the above, but for the benefit of those using the metric system, here is how I would calculate it...

let's assume you want 800 litres of 12P wort

12P = 12g sugar/100ml wort = 120g sugar/litre wort
therefore in 800 litres = 800 litre x 120g = 96,000g = 96kg sugar

assuming 80% extract efficiency from your malt
you require extra malt to achieve the 96kg
ie 96kg/0.80 = 120kg malt

if you also want to add an efficiency factor for your brewhouse (say 80%)
120kg/0.80 = 150kg of malt

I find the plato scale makes much more sense in this respect than using points of gravity, but it is pretty simple to convert over.

Allan
Tanglehead Brewing Company
Albany, Western Australia

[GarySped]

Basic Brewing Calculations

Good information on this discussion. While I do not use the following book much myself (as I test beer not make it) I recommend "A Handbook of Basic Brewing Calculations" by Stephen R. Holle and endorsed and published by the Master Brewers Association of the Americas (2003 - ISBN: 0-9718255-1-3).
It is presented in a neat easy to follow and understand format and covers most issues of relevant to the modern day brewer.

[Hofer]

Brewing software

I am trying to calculate my first grain bill...

After you know to calculate it manually check Brewsta soft (brewiki.org).
It is for free and makes things more understandable.

Leonid