Recently I’ve gotten to a point in my brewing where the number of recipe ideas in my head is greater than my capacity to drink or give away my beer. For anyone who comes over my house, this is a good problem — I’ll probably hand you a pint glass and tell you which keg I’m trying to finish. For me, however, this presents a (real) logistical issue. How do I bring all of my recipe ideas to life without committing a full saturday and a full 5 gallon’s worth of ingredients to a potentially mediocre recipe?
Allow me to introduce my 1-Gallon test batch system. With it, I can brew all-grain test batches in record time with minimal additional equipment, effort, cost and cleanup. If I like a batch enough, I can scale it up using BeerSmith to get a full-sized recipe. If I want to tweak an ingredient, it’s easy enough to re-brew. If I hate the recipe, it’s not like I’ve invested any significant amount of money or effort so I have no qualms dumping the batch.
A large (>5 Gal) brew kettle, although you could probably get away with a 2 gallon pot. You probably have this already.
A 5 gallon capacity paint strainer bag.
A 1 gallon glass jug for fermenting. A #6 drilled stopper and a normal airlock (check your local home brew store) fits the mouth of this jug.
The process is essentially just a small scale brew in a bag technique. I heat my strike water in my brew kettle (above) to the proper temperature. I then add my grains to the strainer bag, and lower the whole thing into the kettle. After a few stirs, the mash temperature will generally settle in the desired range. At this point, the name of the game is to keep the mash temp constant. The way I do it is by wrapping the kettle with a few towels for insulation. After the mash is done (I let it go about 75 minutes), simply lift the grain bag out of the kettle and allow it to drain for about a minute before you toss the spent grains. If you’ve done your math correctly (using your brewing software) you should now have an appropriate pre-boil volume of wort at the appropriate gravity. Now, simply start the boil as you normally would. Since it’s such a small batch, I usually just chill the wort in an ice bath rather than using my wort chiller. Add that to the list of equipment I don’t have to clean at the end of the day. When the boil’s over and everything is cool, I just rack into a sanitized jug, pitch an appropriate amount of yeast, and I’m done.
All together, the entire process takes about half or 3/4 the time of a full 5 gallon all grain brew day. And since you’re mashing/sparging/boiling all in the same vessel, clean up is a breeze.
A note about efficiency: On my first time through this process, I noticed that my efficiency dropped about 10 points to around 60-65%. This is to be expected from this technique, since you’ve got a very thin mash and you’re not really sparging. There are a few ways to tackle this, but the easiest is to simply bump up your amount of base malt to account for the drop. Alternatively, you can keep some dry malt extract around to adjust gravity on the fly if it comes out too low after the mash.