I have a recipe for a 5-gallon recipe and I’m planning to make a 10-gallon batch. I’ve heard recipes do not scale linearly but since I’m only going from 5 to 10 gallons is this close to do a linear scale? If not, any tips for the grains or hops? The fermentation will remain constant because I’ll use two separate carboys as I always have used in the past.
I scale all my grains linearly. I know there are those who only scale the base malt, but I want to retain the proportions that the original had. One thing to take into account is that your efficiency may be lower for a larger batch. OTOH, it may not…
Like Denny, I just double the grains when I do 10 instead of 5 gallons. If your gravity is low in the kettle, you can always add a little DME to make up the difference.
I agree with the others. When I do a 10 gallon batch I simply double the ingredients.
Happy Brewing,
Brandon
I have gotten into the habit of looking at recipes in percentages myself.
2 things change with batch size. Hops bittering utilization increases with size, but not until you are up to pro size. 5 to 10 gallons is no problem.
The other is that your boil-off will be about the same volume, not % if using the same kettle and burner. So if you are used to boiling a 1.080 up to 1.100, with a 10 gallon batch you will only get to 1.090 unless you double the boil time.
Great tips! Thanks for the feedback and advice. I had not thought of the boil off difference and that makes sense; I’m sure I would have gone with percentage rather than volume.
I only brew ten gallon batches, and as most recipes are written for five, I simply double everything. However, The local brew-pub did like one of my recipes, and to scale it up to the four bbl ssytem did take some tweaking. Considering efficiency differences and such. Beersmith made fairly easy though. change the % efficiency, then start tweaking grains and hops to get back to your iriginal IBU, and OG targets.
He went through the eight kegs pretty quick.
I’m gonna have my black IPA on tap there this fall.
AFAIAC, you should ALWAYS look at boiloff as gal./hr., not %. Even though Promash defaults to %, Jeff Donovan advises you to change it to gal./hr. Beersmith only does %. Until that gets changed, I consider it a limitation that makes it difficult for me to use Beersmith.
I just plug the % so it reflects the right gallons per hour. Granted it’s a slight pain but I generally only do one batch size so once it’s set up I don’t have to mess with it for awhile.
Good idea…I’ll play around with that. But I hope they’ll change it, anyway!
Your recipe will not scale perfectly linear, however, if you know a few data points, you can make the correct changes to keep the recipe tasting the same.
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Know your final gravity and make sure that your yeast will hit the same terminal gravity.
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Know your IBUs and using the brewing software, adjust your additions to keep the same IBUs
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Keep your hop additions after 30 minutes to the correct ratio (scale those up or down based on recipe size) and make any bitterness corrections to your 60 minute addition. That way you keep the “hop flavor” correct and can account for any increase/decrease in efficiency
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Know your different kettles evaporation rate, and different mash tun efficiency rates. Calculate your grains accordingly (I usually keep the same ratio and just bump up or down the grain bill to compensate for efficiency. Keep in mind the goal is the same final gravity, but if you are splitting the 10 gal batch into fermentation vessles simlar to what you use for 5 gallons and pitch the correct yeast strain/qty… the OG should work too)
So while for the most part you can go linearly in your recipe, just check these few items to be sure you do not need to “fudge” the recipe a bit to account for non-linnear conditions, usually associated with changing equipment or boil size.
In the end, even if you do not consider these few items, the beer will turn out great! So as with most things in homebrew, you can sweat as many or as few of the details as you like!
I scale my recipes in an effort to achieve the same end product. By that I mean the same OG, FG, IBU’s, ABV, color , etc…
For the grain bill I adjust the weight while keeping the same percentages. Hops are scaled by keeping the IBU’s the same. Yeast is adjusted by unit volume and OG as per mrmalty.
Water is adjusted in accordance with the final volume desired.
Starting volume = final volume + grain absorption + evaporation (boil-off)
Boy, did I read that wrong at first glance. I took it that you scale all your recipes (ie. APA, Stout, Pils, etc.) so that they all end up with the same OG, FG, etc. :o
Thanks dude. You explained what I was trying to say much better than I did.
and I wasn’t drinking beer while I conjured up that thought…imagine that. 
Every now and then I find my feet. ;D
Yeah, that would be nice. I was playing around with it a little tonight. Under evaporation rate in the equipment setup it says “5-15%” next to the field. But that’s just a recommendation. You can put whatever value you want in there. For my next brew, assuming it’s not too humid, I’ve got that set at 23% to achieve 2.5 gallons of boil-off for a 75 minute boil (yeah, that’s a lot; I’ve got a wide kettle).
I feel that gallons per hour is the only righteous way to keep track of my boil-off rates since, given the diameter of my kettle and the intensity I like to see in my boil, I tend to boil off 1 gallon per hour regardless of whether there are 7 gallon of wort in my pot at the beginning of that hour or 7.5 gallons of wort in that pot. Obviously 1 gallon is a different percentage for every batch size depending on whether I’m doing a 90min boil (and I start with 7.5 gallons) or a 60min boil (and I start with 7 gallons). I think the only time I’ve ever seen anything that I felt was substantial that quoted boil off as a percent was:
[quote]The most widely used indicator is the percent evaporation that takes place in the boil (Narziss, 1992). With standard boiling systems, a general rule is that the volume reduction be at least 7%. However, it has been show that evaporation rates above 12% may produce level 2 heterocyclics, leaving vegetal malt tones that are accompanied with some astringency. A wide range of level 2 and 3 heterocyclics is possible once evaporation rates exceed 15% As already stated, the flavor of the finished beer will determine the extent to which this effect is relevant
[/quote]
- Fix 1999
To me it seems that a 15% volume reduction over the course of a single hour’s time boiling would be more significant to a commercial brewer than to a home brewer but that quote is verbatim so take it with as many grains of salt as you feel necessary.
[quote]I’ve got that set at 23% to achieve 2.5 gallons of boil-off for a 75 minute boil (yeah, that’s a lot; I’ve got a wide kettle).
[/quote]
That seems like quite a bit off boil off. What is the width of the kettle that you use? Remember it’s not the size of your kettle it’s the motion of your wort 
My 10 gallon kettle is 15 inches wide. The new one I just picked up is a 15 gallon that is 18.5 inches wide but I haven’t taken that out for a test drive yet. I’m going to work on keeping my boil just barely roiling to hopefully bring that evaporation rate down some.