hey tk, how are you calculating you're total needed water?
i've read a couple different things and thought i'd ask.
Well I cheat and use software called BeerSmith which gives you all of the calculations, but you can get very close by running a few numbers. If you are using one pot, it's very easy.. two pots makes it a little more difficult. Here are some numbers for a 5.5 gallon batch w/ 13lbs of grain. I'm padding the batch size by .5 to account for cooling and trub loss.
Two Pots:Mash volume
– Multiply the total grain bill by the quart volume (typically 1.25). Anywhere between 1 and 1.5 qts is fine.
Next, figure out your:Absorption
– Account for absorption at the rate of .1 gal per pound.Boil-off
– This differs per elevation…ours is around 1 gal per hour (depending on how hard you boil).
To get:Sparge volume
– Calculate by adding the absorption, boil-off, and difference between your batch size (5.5) and mash water volume. A typical scenario would be:Mash water
= 13lbs x 1.25 = 16.25qts / 4 = 4.1 galSparge water
= (5.5 – 4.1) + (13lbs x .1) + (1 gal boil-off) = 3.7
Total volume of water needed = 7.8 gal
For no-sparge BIAB like I do now, just start with 6.5 gallons (which includes boil-off) and add the amount of water that will be absorbed by the grain. 6.5 + (13lbs * .10) = 6.5 + 1.3 = 7.8
See why this is easier!
It's the same as with all of this stuff. Don't worry if it's not perfect. So you're off a 1/2 gallon somewhere--it will be fine and you can make an adjustment next time.
That's pretty slick. How many pounds of grain do you think your bag (or your back) can handle moving around?
keyword "back" lol. The most I've done is a Dogfish 90 clone which had 36 lbs, and this was before I made the drain tub (which most certainly would have helped). All I could think to do is put up a ladder so I could reach down and lift with my shoulders and arms from above. My wife put the paddle in and it drained. As you can see, the bag is wider than the pot when removed, and this is a 15 gallon kettle! haha. This much grain did put quite a lot of stress on the bag and it held like a champ. I've since purchased another bag and when I have a grain bill like this, I double them up. Most aren't though.