Batch sparge temperature without a mash-out

I'm planning to do my first batch sparge, and I haven't been able to find any formula to use to figure out what the temperature of the sparge water needs to be.

I know that the temperature of the water, once I've added it to the grist, should be about 168 degrees. But the grist is not going to start out at that temperature, since my mash is going to occur at 151 degrees (I'm not doing a mash-out). So after I drain the mash water, the wet grist is probably going to be somewhere around 145 degrees, I'm guessing. Anyway, my sparge water is going to have to be at a higher temperature than 168 in order to bring the grist + sparge water temperature up to 168.

I was hoping to find a formula that would take as parameters the temperature of the grist, pounds of wet grist, and the amount of sparge water, and tell me the required temperature of the sparge water to reach 168 degrees in the mash tun.

Anyone know of such a calculation? I'm looking for a mathematical formula that I could create in Excel, rather than a black-box calculator such as the one on beertools.com.

Thanks,
Shaun

I'm not saying that knowing the math is a bad thing, but all of the "black box" software does a fine job. Since arriving at an exact temp is not all that important, a rough sparge temp of 185F is about right. It will get you to about 167F after you stir.

Your grist will not cool off as quickly as you think. If your mash is at 151 before runoff, I expect it will still be right around there after your runoff. It might drop a degree or two, but not down to 145 (that is, if you keep it covered while lautering).

Also, if you split your batch sparge, remember that your bed already up to temp. You don't need water that is at hot. I'm not saying you would forget. I'm just speaking from experience, here.


TL

168-170 F is what I use for batch sparging. Works like a champ. I split my batches into 2 equal sizes.

Certainly you can be happy with 168F sparge water, but your efficiency is about 5-10% lower than it can be. However, you didn't mention if you do anything to raise the mash temp up prior to sparging so that's a detail that may negate my comment completely.

I don't think you can really come up with a calculation that will be very close. Different setups with leave different amounts of liquid behind. This left behind wort will affect the temp when you add the sparge water in. Also, different setups run and different rates and people may sparge with the lid of the MLT on or off which will also affect cooling. I think you best bet is going to be to come up with what works in your system.

I use a 10 gallon Rubbermaid. I do two sparges of equal volume and since my gain bed is 148-154 depending on the brew. I generally use about 180 degree water for the first sparge. This usually gets me into the 165 range and then I use 170 or so for the second sparge to try to get close to 168 but not go over.

On the batch I did recently, I used 10.5 lbs of grain and mashed at 153. I do a double batch sparge and I found that 182 degrees on the 1st sparge brought the grain temp up to 168. I did the second sparge with 175 degree water and the grain bed temp was 165. Seemed to work good enough for me so those will be the temps I'll be using going forward... give or take a couple degrees.

I know this is an old thread, so forgive me. If you're doing a double batch sparge, are you draining the tun after the first sparge? Or are you adding water to bring the temp to 165 or so, letting it sit, and then adding the 170 water and at that point draining the whole thing?

Drain it off in between.

I know this is an incredibly old thread, but thought I would post a formula to figure out your sparge temp. This is reversed from the infusion formula in "How To Brew":

Tw = ((T2- T1)(((.2G)4) + Ds) / Wa) + T2

T2 = Target Temp
T1 = Current Temp
G = Grain bill in lb
Ds = Dead Space
Wa = Amount of sparge (qt)

Multiply .2G by 4 to get from gallons to quarts. Ds not obvious from the original formula, but it is based on the fact that residual heat is still in the Ds.

This gets me very close to where I want to be temp-wise.

I was getting horrible efficiency (50s to 60s) batch sparging with 168 degree water. When I started double batch sparging with 2 equal volumes at 190 and 180, respectively, my efficiency finally got over the 70% threshold. So relieved!