Applying generic recipe to specific batch size?

[3dB Brewing]

Mitch Steele's (otherwise) excellent book IPA concludes with recipes for historic, early craft, and modern IPAs. The grains and hops are presented in % per gallon. How do I translate that into lbs and ozs for a 5-gal batch size? For example, Harpoon IPA:
Pale malt 94%
Victory malt 4%
60L Crystal malt 2%
OK... 94% of what???
Similarly for the hops. The recipe is 9% Apollo at 65 min, and Cascade 19% @ 20 min, 35% @ 5 min, 36% @ WP.
Again, 9% of what? I don't know how to add 9% hops to the kettle -- I do know how to add 1.75 oz. of hops!
The recipe specifies "targets:"
OG 1.062
FG 1.013
ADF 77%
IBU 62
ABV 6.10%

The author implies that a specific recipe can be derived from those targets -- "a calculation can be made" for the grain bill; and "you will have to calculate the utilization for your equipment" to derive the hop additions -- but without the slightest hint what that means or how to go about it. Given the level of detail on other topics in the Appendices, it seems a rather glaring omission, and one that severely limits the utility of the book for inexperienced brewers.

This has got to be a common question -- is there a tutorial somewhere?

 

[BrewnWKopperKat]

AFAIK, percentages are based on weight.

One approach would be to use recipe software that displays ingredients in percentages.

Another approach would be a "back of the envelope" initial recipe, then "dial it in" over a couple of batches. With malts, I know how to "do the math" for my system. If I had to convert hops, I'd start with a similar approach. The recipe would be a starting point as each set of equipment will produce a different beer). A number of years ago, my homebrew club had each member brew the same recipe - Each beer was different.

There are a couple of people here who are much better at the math (e.g. @VikeMan) than I am. Hopefully they will show up to offer advice. It's a holiday weekend, so give them a couple of days to show up.

 

[VikeMan]

Grains as a percentage of total grain weight, along with a target OG, is a pretty common way to specify a grain bill, because the actual total weight you'll need will depend on your mash efficiency (and of course your batch size), which the recipe author obviously doesn't know.

Specifying hop additions as a percentage of total hops is less common. But as long as you know the target IBUs, you can make it work.

But you'll need software, unless you want to spend hours on a single calculation for the hops.

My excel workbook BrewCipher can scale the ingredients, given OG and IBU targets. If you use it (or any software), you should first set up your brewhouse profile (dead spaces, boil off rates, etc.) before building a recipe. But even if you don't, you can see how the scaling works.

For the grains for example, you can just enter those percentages as whole numbers (e.g. "94" for the pale malt, etc.), enter your target OG (1.062), then hit the "scale" button. Done. You can do the same for hops, with the IBU target. You can even scale them both in the same pass, with the "combo scale" button.

Even if you weren't trying to scale a recipe, I'd recommend using some kind of software. I can't imagine doing all the calculations by hand routinely. Actually, I can imagine it, and it's horrifying.

 

[Zemillard90]

I believe the percentages are not referring to % per gallon, but % of the total grain bill (similarly for the hops as well, notice how both add to 100%. Well the hop %s add to 99% but close enough). As @BrewnWKopperKat suggests, using a software (such as beersmith like I do) helps, but is not required. It does however help to know a sense of your brewing efficiency to calculate the gravity estimates.

So looking at your example above, I would just start by assuming a 10# grain bill (total grain used in the recipe) for easy math. You would need 9.4# of Pale Malt (94% of 10#), 0.4# of Victory Malt (4% of 10#) and 0.2# of Crystal 60L (2% of 10#). Plug in your efficiency (again, easier with software or some online tools) and see what the estimated OG comes out to (I think 10# would be short of the OG listed for this recipe). If the estimated OG is too low, try again but start with a higher total grain amount.

The concept is the same for the hops, but refers to the total hop amount used. The number you are trying to match with the clone recipe is the IBU amount. Adjust accordingly until your estimated IBU matches just as you adjusted the grain amount until the estimated OG matches the recipe.

Hope this helps! Cheers!

 

[tracer bullet]

So looking at your example above, I would just start by assuming a 10# grain bill (total grain used in the recipe) for easy math.

This is exactly what I do as well, conceptually anyhow. For a 1.062 OG prediction, I might start with 12 pounds and do the math but the gist is the same. Run the %'s in a calculator (I like brewer's friend) and go from there. Don't have to get it exact, if it's really close I might just fudge the base grain a half pound either direction and not recalculate the rest of it. If I like the recipe there's a guarantee I'll tweak it the next time anyhow.

 

[3dB Brewing]

I believe the percentages are not referring to % per gallon, but % of the total grain bill

I think they're the same thing (94% 2-row pale malt is 94% of the total, but also 94% of the grains per gallon, no?). Anyway, I was paraphrasing the author. Here's the quote:
"For the recipes, I opted not to give specific weights for brewing five- or 10-gallon batches. Instead, I provide percentages and weights on a per-gallon basis, so you can construct the recipe based on your own brewhouse size and efficiencies."

I downloaded BrewCipher. Impressive program. Leaving most of the brewhouse page with the defaults (because I have no idea what other numbers to use), on the recipes page when I try to select the percentage next to the grains, it tells me the sheet is protected and asks for a password. Do I need to buy that?

 

[3dB Brewing]

Plug in your efficiency

Mash efficiency? I see that term bandied about. How do I calculate/estimate that?

 

[VikeMan]

I downloaded BrewCipher. Impressive program. Leaving most of the brewhouse page with the defaults (because I have no idea what other numbers to use), on the recipes page when I try to select the percentage next to the grains, it tells me the sheet is protected and asks for a password. Do I need to buy that?

There's nothing to buy! The percentage column is protected because those values are computed (not user entered). Enter Mitch's recipe's percentages as if they were whole numbers in the "Lbs." column (e.g. simply "94" (without the "%") for the 94% pale malt, etc.), enter your target OG (1.062), then hit the "scale" button.

(As long as the amounts entered are in the right proportions to each each other, it will work, but I would avoid entering the "%" character in those cells. The scale function would still work, but you'd be inadvertently changing the display format of the cells.)

Regarding the brewhouse parameters, if you hover over the cells, most of them have popup hints. I'd recommend at least checking out the ones in the Volumes and Volume Losses section before brewing. But if in doubt, you can leave the defaults, or give a yell if there's anything you're stuck on.

 

[3dB Brewing]

There's nothing to buy!

Cool! I'll play around with it some more; there's a lot there!

 

[VikeMan]

Cool! I'll play around with it some more; there's a lot there!

There's also a detailed user guide you can download from the same site(s). But AFAIK, nobody has ever actually read it.

 

[tracer bullet]

Mash efficiency? I see that term bandied about. How do I calculate/estimate that?

There are apps and online calculators. Think of it as what % of the available sugars did you get from the grain with 0 meaning you didn't even get it wet and 100% meaning you couldn't have done any better.

I like Brewer's Friend. Take your next grain bill and plug it in with your volumes and etc. Make sure you measure your gravities along the way. Then go and tweak that efficiency number until you get one that allows your grain bill to match the gravities you actually obtained.

 

[VikeMan]

For @3dB Brewing, note that 100% mash efficiency (a measure of the percentage of theoretically available sugars and dextrins that actually make it into the boil kettle) isn't possible. 100% conversion efficiency (the percentage of starches from the grain bill that are converted to sugars and dextrins) is possible, but not all of the sugars and dextrins will get to the kettle. Some will be left behind in the grain bed. And some may be lost to dead spaces, hoses, etc., depending on your mash tun setup.

If you have no idea at all where to start, I'd suggest using a mash efficiency of 70% in your calculations the first time, then adjust as needed based on what you measure.