Experimenting with Batch Size: The Smallest Possible Batch

People are often curious about why I brew lots of incredibly tiny batches. For me, the answer is simple: I like to experiment as much as possible without dedicating an entire room to fermenting carboys. Experimenting in small batches means I can try out lots of different recipes all at the same time. I like to tweak my recipes before scaling them up anyway, so it works out really well to make a batch that is smaller than 1 gallon. So now for the big question that’s been on my mind for a while now...

How small can a batch get?

Having already brewed a number of successful batches in the 32 - 64 oz range, it seemed plausible to make batches smaller than 32 oz. Scaling everything down beyond 32 oz wasn’t too hard, bringing the water to boil was quicker, and overall the beer turned out great. Keep in mind that at the time I had only been brewing extract recipes, so that made this process a bit easier.

Once I got into all-grain brewing using the BIAB (brew in a bag) method, I did find that small batches were not as easy. In the extract brews, there was no need to maintain mash temperature for such a small volume of water, among other things. However, after reading this article from Brulosophy, I was surprised to find that extreme mash temperatures wouldn’t end up ruining my beer outright. I began to wonder not only how small of a batch I could go for extract, but for all-grain as well, and would those “minimum” batch sizes be similar or worlds apart? My hope was that untamed mash temperatures wouldn’t stop me from scaling down my mash as small as my extract experiments.

I added some of my more regular sized batches as a reference to my findings. The notes are hardly scientific, but it might help you avoid some of the mistakes I made.

Extract RecipeBatch SizeHighlightsIssues
Pale Ale64 oz (½ gallon)Fits well in my 1 gallon carboyWon’t fit in a 64 oz growler without a blowoff tube.
Amber Ale48 ozFerments well in my 64 oz growlerNone
Amber Ale32 oz (¼ gallon)Fermented this in a 1 gallon carboy and it worked out fineNone
Pale Ale16 ozFermented in a 16 oz flip-top and bottled in a 12 oz. Dry-hopped in the fermenter for the entire fermentation period.None
Blond Ale12 ozBoth fermented AND bottled in the same 12 oz bottle. Dry-hopped from the start of fermentation; left in the bottle; No taste issues due to fermenting in the same bottle that it was served from.None

All-Grain RecipeBatch SizeHighlightsIssues
Russian Imperial Stout101 oz (~¾ gallon)Fits well in my 1 gallon carboy. Temperature control was easier than smaller batches.Requires a lot more stirring than smaller batches to get an accurate temperature reading.
Dunkelweizen37 ozFits well in my 64 oz growler. Easy to boil in a saucepan.Difficult to maintain mash temperature. Ranged between 145 - 162 F. This can be mitigated slightly by covering the boil saucepan. Ended up with a few flavor issues due to mashing too hot.
Altbier37 ozCovered while mashing to better sustain mash temperature. Reduced mash temperature range by a few degrees.Difficult to maintain mash temperature, but less so when the mash was covered from the beginning. Ranged between 150 - 161. Ended up with lots of flavor issues due to mashing too hot. At this point, I also discovered that my pH was too high and I was getting lots of tannin extraction, so future batches will have that adjusted.
Simple Altbier18 ozMash temperature was easier to maintain in a double boiler. Added 3.5ml of fresh lemon juice to lower the pH. Taste turned out unaffected by the lemon, but tannins/astringency was greatly reduced from the 37oz Altbier brew above.The double boiler meant additional equipment and difficulty transferring to a saucepan for boiling. I don’t recommend it unless you have an easy way to transfer the wort.
<Planned>8 oz