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Converting 1 or 5 gallon recipe to 3 gallons

I brew 1 gallon AG recipes and I’m now fairly confident in my process and want to upgrade to 3 gallons. A few questions

1 - How do I convert 1 or 5 gallon recipes? I’m mostly concerned that the mash and sparge water volumes won’t be exactly right if I simply multiply a 1 gallon recipe by 3.

2 - I have pots that are big enough but wondering if a 5 gallon carboy would be ok to use for only 3 gallons. I have 3 x 1 gallon jugs which I assume I could use as well though that may be annoying.

I realize the easy answer would be to just brew 5 gallons, but I’d rather not buy and store all the extra equipment.

I use Brewer’s Friend and enter the recipe, then use the built in scale function. Do it all the time with 5 gallon recipes. I do BIAB at 3.5 gallons into my fermentor. I use the 5gallon plastic carboy from NB for fermenting, works great.


Easy enough to multiply by 3 for your batch… I think the only time you’d run into problems id with hops at a much larger scale… Sneezles61

All my AG batches are 3-gallon; it’s a great batch size. I also do 5-gallon extract batches. I generally use my 5-gallon carboys as primaries for my 3-gallon batches. Works great.

I also use BeerSmith to scale 5g recipes to 3. But you do get some inconvenient numbers. So I usually round the numbers manually. Maybe move the time of additions to keep the IBUs.

Mechanically, beer recipes do scale. The one thing that stays pretty constant is the boil-off rate of a given system.

One piece of advice. Don’t get wrapped around the axle about precisely scaling recipes. There is art and science in brewing, embrace the art too.


Yes indeed. Be creative. Do the math by calculator. And paper. Once you done. With the recipy. And got it worked out. Plug all the info in a brewing software. See if it did come out. Me when i did find a recipy i do like. But its a 5 gall. And i need to up scale to a 10 gall. I use old fashion pen calculator and paper. And the formulas. Once done. I do use brewers friend recipy calculator. See if i am on the right path

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I brew 20 gallons and also simply multiply 5 gallon recipes by four. Depending on style if the hops come out to a partial amount like 4.x oz I will round up for something like an IPA or down for something less hoppy.

After the ingredients are quadrupled I use standard AG volumes like 1.25 quarts water per pound of grist. The only problem I have had is occasionally the color will not come out as expected. This could be a problem with the amount of specialty grain or how close the listed SRM is. I really don’t care if it tastes good.


thanks all. gonna give it a whirl.

Just one quick additional question. I brewed this yesterday and had pretty good efficiency though I yielded more like 2.25 vs 2.5 gallons. How do folks sparge for this amount? For 1 gallon I just manually pour the sparge water over the grains (on a colander) into a bucket and then repeat 3x. Yesterday I tried BIAB but it felt kinda clumsy.

I do not sparge for BIAB. I finish the mash, pull the bag from the kettle and gently squeeze any absorbed wort out. I usually rest it on a grate above the kettle and let it drip until it is mostly gone. I’ve been averaging between 67% and 70% efficiency this way. That is the beauty of BIAB. It’s a one step process.

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My approach to BIAB is to keep it simple. So I typically don’t sparge.

When I convert recipes for my system, I use a slightly lower efficiency (e.g. 75%) than my typical efficiency (e.g. 80%) as it is easier for me to get to the recipe OG by adding water.

How would I make the adjustments when the wort size was 10% lower than expected? It would depend on the pre-boil SG:

  • If the pre-boil SG was “in range” with the recipe OG, I’d accept the wort size, perhaps reducing the bittering hop additions by 10%.
  • if the pre-boil SG was higher than expected, I’d add water to get to the target SG.
  • if the pre-boil SG was lower than expected, I’d probably add water and light DME to get to the recipe wort size and recipe OG.

Hopefully you did document all you did… Then you can figure out how much you need adjust… Sneezles61

thanks all. Great feedback. I can’t believe I’m so late to the BIAB game

BIAB appears to have started around 2007 (see link below), so if one assumes that people will continue home brewing for (say) 500 years, you’re actually quite early to the BIAB game. :wink:

Beer Forum • View topic - How to go from Extract to AG for < $10.00 - the first post in this thread is one of the better BIAB overviews that I’ve seen (i haven’t read the comments or resolved the ‘broken’ links :confounded: ).

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