Brewing small batches has its advantages – it’s quick (I can normally knock out a batch in about 3 hours flat), it’s great for experimenting and not worrying about wasting too much time/resources if things don’t turn out well (most of my early sours were small batches), and it’s more manageable for brewing indoors for me at least. Here’s my standard process for making a 3-gallon batch.
Using brewing software I usually design the recipe for slightly higher volume (3.5 gallons) but with target gravity IBU/color/OG that I want. I’ll lose about 1/2 gallon to trub and i’ll be diluting the wort slightly with ice (more on this later).
I use the brew-in-a-bag method in a 4 gallon stock pot. Mash-in like normal, usually around 1.5 to 1.75 qt/lb, calculating such that you’ll have around 3 gallons of pre-boil wort. I realize this seems low for a 3-gallon batch, but hear me out. Rest the mash for however long you want – around 45 minutes works for me. I usually don’t do step mashes; it’s more work and I’m usually focused on speed for small batches. Mash-out if desired, making sure to consistently stir while you heat since there’s no pump for recirculation. The mash near the base of the pot will get significantly hotter than the surface otherwise.
Lift the grain bag out of the pot and then use a pasta strainer to hold up the bag over the pot and let it finish draining. I have a nice metal one with the handles of the strainer wide enough such that it’ll just rest on the edges of the pot, suspended above the hot wort. To sparge, I’ll either pre-heat some water in a side pot, or, if you’re super lazy like me, use an electric tea kettle to heat up water in small batches and then drizzle it over the suspended grain bag, making sure to wet all parts of the bag evenly. It’s super effective, and I usually get pretty good efficiency in the 75% range. The tea kettle only holds about 1.5 liters, so i usually do two rounds of water to get my pre-boil volume up to about 3 gallons. The tea kettle is design to boil the water, so just watch it witha thermometer until it gets to 170F and then you’re good. While you’re sparging, start bringing the wort to a boil.
Boil like you normally would, just watch closely for boil-over.
I don’t have a good way to use a wort chiller indoors on my kitchen sink, so I use a less-than-ideal but still very practical way of chilling down to pitching temperature. Ice. Just dump as much ice as your freezer can hold directly into the hot wort. Yes, this will dilute the wort, and yes you’re adding unsterilized water to the batch. Don’t worry – it turns out great every time.
The amount of ice you add will affect how low the temperature gets. Mine usually only gets down to around 110F to 120F. At this point, if it’s cold outside, I’ll sit the kettle outside (covered) until the next morning and it’ll usually be around 60F. Or, if you have room in a refrigerator, that’ll work too.
After the wort chilled to pitching temperature, use a funnel to pour it straight from the pot into your fermentor. I use regular 5 gallon glass carboys. There will be a good layer of trub that has settled to the bottom of the kettle – it’s up to you whether you transfer this to the fermentor, but I usually stop pouring as soon as i hit the trub and discard the rest. You do lose about 1/2 gallon or wort, so be sure to factor that into your water volumes.
I usually don’t make a starter since the volume of wort is less. That being said I usually feel way more confident about the fermentation quality if I use a starter, regardless of whether it truly makes a difference in flavor. If it’s a stronger beer (>1060) I’ll make one regardless.
This all may seem a little hacky, but it’s easy and effective. It took me a couple batches to hit my numbers, so don’t be discouraged if you go through this and wind up with only 2.5 gallons rather than 3, or 1045 wort instead of 1050. Just adjust accordingly for the next batch and it’ll work out fine. Good luck!