Let’s say that you have a 5 gal recipe, but really don’t want to waste 5 gallons on a beer you might not like. Is there a system or calculator out there that can convert the mats for the 5 gallon into the necessary mats for a 1 gal? Or even a 3 gallon? I realize that 1 gallon brews only produce maybe 10 bottles, so I could settle with a 3 gallon.
I’m also a little curious, when pitching yeast, would you still use the whole packet (wet or dry) for a 1-3 gallon?
When converting recipes from one volume to another, everything scales directly except for volume losses due to boiling or equipment “dead space” issues. So if you normally do concentrated extract brews, it’s very easy because you take care of the volume issues with the top up water at the end.
Example: 5 gallon recipe:
6.6 lbs LME
1.5 lbs specialty grain for steeping
1 oz bittering hops
1.5 oz flavor hops
2 oz flameout hops
1 pkg dry yeast
Conversion to 3 gallon recipe:
6.63/5 = 4 lbs LME
1.53/5 = 0.9 lbs specialty grain for steeping
13/5 = 0.6 oz bittering hops
1.53/5 = 0.9 oz flavor hops
23/5 = 1.2 oz flameout hops
13/5 = .6 pkg dry yeast
In cases, you’ll boil at about 1/2 - 2/3 your recipe size, then top up at the end.
If you are brewing AG or are using full-volume boils for your extract brews, it gets a bit more complicated because the volume losses don’t scale directly. For those situations, it’s worth getting brewing software.
The bigger issue with scaling, in my experience, is that purchaseable increments remain the same. No one sells hops in less than 1-ounce increments. Similar situation with liquid extract, our host sells in 3.15 or 6 lb jugs. I think more beer does LME in boxwine bags in 1 pound increments. My LHBS guy was talking to me about someone coming in looking for 0.15oz of so hops and being mad at him because he would only sell by the full ounce.
So if you have a 5 gallon recipe that calls for 1 ounce of a hop variety, when you convert down, you’ll need 0.6 ounces to make a 3-gallon version. What do you do with the other 0.4 ounces? If you waste it then you’re adding significant cost to the brew. I’m convinced there is no practical way to get 3.6 lbs of LME from a 6 lb jug, so you have to get the 3.15 and accept the lower gravity, which impacts the hop balance too, or boost with a bit of DME.
My process is to enter the recipe in Beersmith, scale it down, then tweak the amounts to more manageable increments, the calculators let me tweak with not-too-much deviation from the original. It helps to be familiar enough with the base recipe so you know which way to tweak. For example if you’re looking at adding 0.66 lb DME to be perfect, maybe you could use a full pound or a half-pound instead? Which direction to go a trade-off, that depends mostly on your personal taste.
I’m AG now, and buy hops in larger increments so I can take what I need and vacuum-seal the rest, both changes made recipe scaling easier.
