Ques About Batch Sizes

[raptoid]

I'm ramping up for my first all grain session soon. I look at recipes and they'll say 5 gal batch size, 6.5 gal batch size, etc. My question is this; How do I know how much strike water to heat up to equal out a 5 gal batch? I realize that I'll be adding sparge volume as well. Would I just strike and mash with 5.5 gallons, at the end of mash duration begin sparge and keep going until I have a volume in the boil kettle of around 6.5 gallons? Then after boil off I'll end up with 5 gallons?

I'd imagine I would strike a lot more water than the mash needs, and then the remaining strike water would then be used for my sparge. I also realize that there will be water loss from grain absorption. Just looking for some clarity around the process, since I know it's a vital part of proper AG brewing. Thanks in advance!

 

[GrogNerd]

work backwards from how much you intend to bottle

figure out how much bottling loss, fermenter loss and boil-off loss and add to get how much you need pre-boil

figure out your strike volume. this is anywhere from 1 to 2 quarts per pound of grain. this ratio depends alot on style and recipe, but also on personal preference.

figure out loss due to grain absorption (pretty much a constant 1 fluid oz per oz of grain) and any dead-space in your tun (totally dependent on your equipment). subtract this from your strike and that should tell you how much your first runnings should be

your sparge amount will depend on how much first runnings you get. start with however much water your first runnings are short of your pre-boil volume. don't need to account for grain or dead-space loss in your sparge amount, you should get as much water out as you put in

 

[Pie_Man]

Brewing software helps a lot as the math can be tedious. I recommend downloading the beersmith trial version.

 

[bobeer]

To get my strike volume I just multiply my total amount of grain by 1.25 quarts. You can times it by 1.50 quarts for a thinner mash if you want; just depends on what you're brewing.
So, if I had 12 lbs of grain I'd do 12x1.25=15 quarts and 15 quarts is 3.75 gallons

As far as sparge volume is concerned I usually just sparge until I reach my boil volume. There's other ways to figure out exactly how much sparge water you'll need but I'll leave that for you to search the forums for

You'll need to figure out your strike temperature too. Just google for a strike temp calculator. I have an app on my phone that does strike temp and it's always on the money. It just takes your total amount of grain, the temperature of the grain, total mash water volume and what temperature you want to mash at and it spews out a number.

One more piece of advice... if you're using a cooler mash tun be sure to heat up about a gallon of water and dump it in your mash tun before you add your strike water. I usually let it sit for about 5 minutes then dump it out right before I add the strike water. You want the mash tun heated up so it doesn't bring down the temperature of your strike water/mash. My first all grain mash was about 10 degrees cooler because I didn't heat up the mash tun before hand.

Good luck!