Essentially, I brew 3.5 - 4 gallon, all-grain batches, using a split boil technique on my electric kitchen stove. With this technique, I have no need to move my operation outdoors, buy a giant brew kettle and a bigger chiller, or figure out how I will transfer large quantities of liquid (I know lots of brewers manage this, but for me, it would be a huge change in my process and equipment, so I have no desire to do so - especially since my process works so well).
When thinking about moving to all-grain, I realized that my limiting factor was how much liquid I could heat on my stove. The simplest solution I decided was to use two kettles - both for heating my strike water and for collecting the wort and brewing the beer. Filled to the brim, my kettles each hold 3 gallons. Safely, I can boil 2.5 gallons of wort in each. This is my limiting factor - I can only collect 2.5 gallons of wort in each kettle. So, my strike water volume is calculated by determining how much I will need so that I collect 2.5 gallons of first runnings. This means that my strike water volume is calculated based on how much grain I am using in my recipe.
Grain absorbs approximately 0.5 quarts of water per pound and since I want to collect 10 quarts of runnings (2.5 gallons), I calculate my strike water volume (in quarts) as 10 + 0.5*G, where "G" is equal to the total weight of my grains, in pounds. What this means of course is that my water-to-grist ratio for my mash changes batch to batch, depending on how much grain I'm using in the recipe. I'm generally between 1.5-2.0 qts/lb on most of my brews and I haven't noticed any differences:
|Grain (lbs)||Strike water (qts)||Water-to-Grist ratio(qts/lb)|
Of course, since I need to heat more than 2.5 gallons of strike water, I need to use both kettles for this as well. For more consistent results, I actually boil 2 gallons of strike water and then calculate how hot I need to heat the additional strike water. For example, for my last batch, the Belgian Tripel, I had 8 lbs of grain in the mash, so I needed 14 quarts (3.5 gallons) of strike water. I boiled 2 gallons in one kettle and heated the other 1.5 gallons to approximately 90-92°F. When combined in my mash tun the temp was 160°F. When I added the grains, the mash temp hit a perfect 148°F. Like I said, my process is a little complex, but it works.
I add any necessary mineral additions to the mash let it go for 60 minutes or so. I then lauter into one of my kettles. If it all works out, I get very close to 2.5 gallons of 1st runnings. While the mash runs, I heat 2.5 gallons of sparge water to 180°F. Once the first runnings are drained, I so a single batch sparge with the entire 2.5 gallons. Since the grain has already absorbed all the water it can, when I drain the 2nd runnings into the second kettle, I get approximately the 2.5 gallons I put in. Simple, right?
I then boil both kettles, generally starting the first runnings while sparging and collecting the 2nd runnings, so they're ~15 minutes apart. For hopping, I go back and forth on whether it is truly necessary to hop both boils. Sometimes I do, sometimes I don't, but I am more and more moving towards splitting the hops - 2/3 in the 1st runnings, 1/3 in the 2nd runnings - for better utilization.
When the boils are done I chill each with my immersion chiller and then dump both into my fermenter. I then aerate, take a gravity reading, pitch the yeast, and clean up. I've found that with this technique I can get ~3.75 gallons into the fermenter. My brewhouse efficiency is 72-74%.
I know this is a complicated set-up. I really need to be on top of all my calculations and pay careful attention on brew day. Managing and monitoring two kettles instead of one also adds a little bit of stress. But, like any brew process, it just takes a little time to dial everything in and I am now very comfortable with it. And in the end, I am very happy with the results.