Tips for batch sparging

I recently moved to AG and have 3 AG beers so far. I'm having a fairly consistent problem across all three hitting the estimates pre boil gravity. I use a 10 gallon cooler with a false bottom. Any tips or suggestions would be great.

Hit your temp and stir the crap out of it.

Re-evaluate your crush.

I get my grains pre-crushed at my LHBS. I asked them to tighten up the rollers a bit for me and they are glad to do it. I have noticed a bit of an increase in inefficiency. Make sure you are hitting your mash temps and as mentioned above, STIR STIR STIR. I noticed that helps. I moved to stirring 2-3 times during my mash period. Also, have you tried mashing longer? Maybe 90 minutes? Are you batch sparging or fly sparging? Fly sparging is slower but can help boost efficiency.

A given mash system has a certain amount of dead space from which liquid will not drain and will retain a certain amount of liquid in the grain. You need to get a sense of what that is. There are estimates for how much water grain retains but there is some disagreement since the total retention is some combination of grain retention and dead space. While you can try to use an expected retention rate in qts per pound, it won't be perfectly accurate, since it doesn't describe the dead space in your tun.

What is important to know is how much liquid your system will retain for a given weight of grain. One way to do this is to do a handful of batches with the same total grist weight, and the same target volume. What you do is you make a graduated rod for measuring the volume in your pot, and after you drain the first batch from the mash tun, you determine how much you collected and subtract it from your strike water volume. You then need to add a batch-sparge volume that will make up the difference between what you collected and your target boil volume.

So for instance:
I mash 10lbs of grain with 15qts of water. My target boil volume is 26qts (6.5g).
I drain the first runnings from the mash tun and collect 10qts. I can assume that there is 5qts left in the tun. I also know that I need 16qts more for my target volume, so I batch sparge with that much. Next time I make a 10lb batch aiming for a 6.5 boil volume, I can prepare the 16qts instead of having to overestimate the amount I will need. If I'm aiming for a 5g boil, I can just prepare 10qts sparge water. The important thing to know is that you'll need (in my case) 5qts more than boil volume for 10lbs of grain. You can split that between mash and sparge water however you see fit.

Of course, if you do a 15lb batch, you'll have more liquid retained, but if you measure the runnings, you can determine how much you should add for the batch sparge. If you keep track of how much water seems to be retained by a given weight of grain, you can use that information in the future.

Hope that helps!

double crush took my efficiency from 59-61 to 85+

runoff is slower, though

I just reread that you said "preboil gravity" and not "preboil volume". Oh well.

Are you preheating your tun? Preheating it to the same temps each time? Varying temperatures on the grain? Consistency of crush from brew to brew? Accurate measurements on your volumes? Do you stir your dough-in for 2-4 minutes, wait 3-5 minutes and check the temp, stir and check again? I ask this one as it takes a bit for the temps to 'settle' where they're going to settle. However hitting that temp would effect the wort properties more so than conversion efficiency over the course of 60 minutes. Thus maybe you're dealing with a water or pH issue, crush inconsistency, or inaccurate measurements/volumes?

buzzno said:

Hit your temp and stir the crap out of it.

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For the sparge also

MVKTR2 said:

Are you preheating your tun? Preheating it to the same temps each time? Varying temperatures on the grain? Consistency of crush from brew to brew? Accurate measurements on your volumes? Do you stir your dough-in for 2-4 minutes, wait 3-5 minutes and check the temp, stir and check again? I ask this one as it takes a bit for the temps to 'settle' where they're going to settle. However hitting that temp would effect the wort properties more so than conversion efficiency over the course of 60 minutes. Thus maybe you're dealing with a water or pH issue, crush inconsistency, or inaccurate measurements/volumes?

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Yes I'm preheating the mash tun with adding boiling water for about 10 minutes then draining. Adding my mash water usually around 175 to get to a consistent temperature of around 152 once I add grain. I stir consistently before shutting the lid then stir again at the 20-25 minute mark. I do a valorf then slowly drain usually have about a gallon absorbed into the grain. I then take the collected volume and subtract from the total volume needed for me usually 6.5-7 gallons for a 5.5 gallon batch. I batch sparge in two parts. The only thing I noticed yesterday was my 1st sparge temps were a little off around 164-166 vs 170ish.

breweringbeaz said:

For the sparge also

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Yep. Fill your ton with your sparge water and stir like crazy again then vourlof.

breweringbeaz said:

I batch sparge in two parts. The only thing I noticed yesterday was my 1st sparge temps were a little off around 164-166 vs 170ish.

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If you mean the mash temp (not the sparge water) that's ok. I usually try to get the grain bed to at least 165 on the first run and close to 170 on the second.

Dude how are you going from 175 to 152???

That is a CRAZY drop in temp. I lose 8 degrees after pre-heating my 100 qt mash tun and it was 27 degrees outside.

Losing 23 degrees sounds like your npt preheating you mash tun.

breweringbeaz said:

Yes I'm preheating the mash tun with adding boiling water for about 10 minutes then draining. Adding my mash water usually around 175 to get to a consistent temperature of around 152 once I add grain. I stir consistently before shutting the lid then stir again at the 20-25 minute mark. I do a valorf then slowly drain usually have about a gallon absorbed into the grain. I then take the collected volume and subtract from the total volume needed for me usually 6.5-7 gallons for a 5.5 gallon batch. I batch sparge in two parts. The only thing I noticed yesterday was my 1st sparge temps were a little off around 164-166 vs 170ish.

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You don't need to drain the water. If you need 175 degree strike water, you can preheat the tun with 180 degree water and just let it cool down to 175 before adding grain.

As some others have pointed out, your most likely candidate is probably milling, especially if you're not having any trouble with a slow sparge. Try getting a finer grind.

Resurrection!

I find that recirculation is very important in batch sparging. Many people might say that it's only necessary to recirculate maybe a quart or so, but I find that recirculating the wort several gallons worth helps. Stirring may also do the same thing, but I kind of like the idea of "fly" sparging while also batch sparging.

My process for batch sparging is like this:

1. drain mash tun.
2. add 1st round of sparge water (I sparge 2 times generally)
3. Mix and stir like crazy for about 2-4 minutes
4. recirculate about 1/2 a gallon by pouring it slowly over the grain bed trying not to disturb the area around where the water drains.
5. repeat about 5 times.
6. drain completely
7. Repeat steps 2-6 with second round of sparge water.

Boil!

Are you checking that you have full conversion before you perform the first run off?

Just an aside, but mashout is not necessary when batch sparging. The wort will be boiling before any potential problems would manifest. I have been happily sparging with cold water for many years with no measurable negative impact.

masonsjax said:

Just an aside, but mashout is not necessary when batch sparging. The wort will be boiling before any potential problems would manifest. I have been happily sparging with cold water for many years with no measurable negative impact.

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This may be the case (I have no idea if there are other reasons to have a mashout), but since I boil on a kitchen stove with 2 burners sparging with mash temperature water helps me get to a boil faster and reduce my brew time significantly.