HERMS Sparge Question

[CorgiBrew]

Okay, I'm just about ready to do my first 10 gal. batch in my new HERMS system. By my calculations, to get 10 gal of wort at the end of the brew, I will need about 18 gal of hot H2O for strike and sparge (using batch sparge technique. My keggles hold 15.5 gal., so this is a problem. How do other people get enough hot water for 10 gal. batches using keggles? Should I add fresh water to the HLT after the initial infusion, or could I just strike and sparge with what I have, and add some water to the BK to get the volume/OG right? (or, should I just make smaller batches?)

 

[Yooper]

18 gallons of water seems kind of high for a 10 gallon batch. Where does that number come from?

But, yeah, you'd just add more water to your HLT after you mash in.

 

[CorgiBrew]

18 gallons of water seems kind of high for a 10 gallon batch. Where does that number come from?

But, yeah, you'd just add more water to your HLT after you mash in.

The 18 gal is just doubling the amount Ray Daniels calculates in chapter 8 of Designing Great Beers for a 5 gal batch. It does seem like a lot, but with 20 lbs of grist, there's going to be quite a bit of absorption, plus all of the usual losses for evaporation, deadspace, etc.

I was worried that adding 3 gal or so of fresh water to the HLT I'd mess up my mash temp recirculating through the hex. But maybe I just need to preheat the additional water, or something ... Too bad I can't run my HLT and BK at the same time.

Am I right in assuming that adding the water to the BK would negatively impact my efficiency because I'd be using less water to rinse the grist?

 

[Yooper]

Ah. Well keep in mind the boil off for 10 gallons ISN'T twice the boil off for 5 gallons- it's the same. So, if you boil off 1.5 gallons in a 5 gallon batch with that equipment, you'll do the same with a 10 gallon batch. So, doubling the water isn't correct.

If you add the water to the HLT (as I have to), you won't really drop the temp much. Here's why- the strike temp might be, oh say 168. You transfer 30 quarts (1.5 quarts per pound for a 20 pound grist) to the MLT. You've already got 9 gallons in there (if you started with 15). So, you can add water to the HLT and still be under the 155 degree recirculation, or whatever temperature your HERMS is set at, particularly if you take a few minutes to stir your mash and gradually add the grain before starting the HERMS. Or like in my case, I preheat the MLT with 180 degree strike water, so when I add water to the HLT, it drops to just about the right temperature, or the element kicks on while I mash in.

For a 10 gallon batch, using 20 pounds of grain, you'd mash in with 7.5 gallons. You'd probably have two gallons of absorption. You'd want to start your boil with 12.5 gallons or so. So, I figure about 7.5 gallons of sparge water. Of course, your system may need more or less, but that's what I'd do on my system.

 

[CorgiBrew]

Excellent point about the boil off. Thanks for the other numbers too. Makes sense. Can't wait to crank this baby up!