Adjustments going to a sparge from a full volume mash

[cdoebler]

Hi everyone,

I've read pages and pages of discussions but I haven't found an answer that helps me. I did my first BIAB last weekend with 9 lbs of pilsner. I only have a 9 gallon kettle so with the full volume, I had only about 3/4 of an inch to the top. I ended up with a 64% pre-boil efficiency which I think was because I probably didn't squeeze enough.

With so little space above, I realize I'm limited to about 9 lbs of grain. So to go bigger, I'll need to move to a sparge.

My question is how do I adjust the mash volume? I have to imagine the volume will change the temperature I'm trying to achieve before mixing in the grains. Do you usually a certain percentage for the mash and the remainder for the sparge? I figure I'll probably go with the dunk method for the sparge.

Any help is greatly appreciated!

 

[pretzelb]

How much water did you use with the 9 lbs of grain?

 

[Yooper]

In general, you can mash with 1.25- 2 quarts of water per pound of grain, and then sparge up to your boil volume.

I use a calculator for my strike temperature, and it's usually about 11 degrees warmer than my desired temperature.

One way to see what will fit in your pot easily is to use this cool tool called "Can I mash it?", found on this site with a few other calculators (scroll down a bit): http://www.rackers.org/calcs.shtml

 

[cdoebler]

On a related note, I think I messed up my efficiency measurement. I took a sample pre-boil and it was 1.032. After boiling, cooling and emptying into my fermenter, I took another sample and it was 1.054. If I put those into an efficiency calculator, the preboil was 62% and the brewhouse efficiency was 81%. I can't imagine your efficiency can go up, right??? I feel more confident in the fermenter reading, but I can't imagine my efficiency would have been that good.

 

[cdoebler]

How much water did you use with the 9 lbs of grain?

I added the grain to 7.5 gallons of water.

 

[Yooper]

On a related note, I think I messed up my efficiency measurement. I took a sample pre-boil and it was 1.032. After boiling, cooling and emptying into my fermenter, I took another sample and it was 1.054. If I put those into an efficiency calculator, the preboil was 62% and the brewhouse efficiency was 81%. I can't imagine your efficiency can go up, right??? I feel more confident in the fermenter reading, but I can't imagine my efficiency would have been that good.

It sounds like your preboil reading was inaccurate. Did you cool it to under 100 degrees before taking the reading? Readings over about 90 degrees are notoriously inaccurate (usually low).

 

[cdoebler]

In general, you can mash with 1.25- 2 quarts of water per pound of grain, and then sparge up to your boil volume.

I use a calculator for my strike temperature, and it's usually about 11 degrees warmer than my desired temperature.

One way to see what will fit in your pot easily is to use this cool tool called "Can I mash it?", found on this site with a few other calculators (scroll down a bit): http://www.rackers.org/calcs.shtml

Thank you! When I sparge, will I generally get 1 gallon of wort for 1 gallon of sparge since the grain has probably already absorbed all the water it can?

 

[cdoebler]

It sounds like your preboil reading was inaccurate. Did you cool it to under 100 degrees before taking the reading? Readings over about 90 degrees are notoriously inaccurate (usually low).

I was inpatient and took the reading in the 90's but thought I had adjusted for the temp accordingly, probably not lol.

 

[Yooper]

I was inpatient and took the reading in the 90's but thought I had adjusted for the temp accordingly, probably not lol.

In the 90s is generally ok, with the correction tables.

 

[Yooper]

Thank you! When I sparge, will I generally get 1 gallon of wort for 1 gallon of sparge since the grain has probably already absorbed all the water it can?

Yes. So, if you have 3 gallons of wort in your kettle, and you dunk sparge in 3 gallons of water, you'd end up with 6 gallons (assuming you squeeze a bit after the mash and after the sparge).

 

[cdoebler]

Yes. So, if you have 3 gallons of wort in your kettle, and you dunk sparge in 3 gallons of water, you'd end up with 6 gallons (assuming you squeeze a bit after the mash and after the sparge).

Perfect, thank you very much!

 

[pricelessbrewing]

Good advice from Yooper as always.

As an alternative, check out my biab calculator. Priceless Biab

 

[cdoebler]

Good advice from Yooper as always.

As an alternative, check out my biab calculator. Priceless Biab

I actually used yours for my first BIAB. I just wasn't sure how to make an adjustment to sparging and using a partial volume mash.

Your site worked great and helped a ton, thanks!

 

[pricelessbrewing]

I actually used yours for my first BIAB. I just wasn't sure how to make an adjustment to sparging and using a partial volume mash.

Your site worked great and helped a ton, thanks!

Using mine? Simple, change the sparge volume on the left

 

[bcltoys]

Given if all numbers are the same,if my boil off is say 2 gallons a hour vr's 1 gallon would mash efficiency be better using 2 gallon a hour boil off. Since I'm using more water.

 

[pricelessbrewing]

Given if all numbers are the same,if my boil off is say 2 gallons a hour vr's 1 gallon would mash efficiency be better using 2 gallon a hour boil off. Since I'm using more water.

Marginally, like 2-3% higher, but the cost in propane will easily exceed the savings in grain.

 

[bcltoys]

Got it.

 

[Ozarks Mountain Brewery]

One thing I did years ago when I was experimenting with brew in a bag, mash with water just covering the grain then add 170 water to a five gallon bucket or two depending on the size then pull the bag out and drain then add it to one of the buckets, let it set for 10 minutes then dunk up and down and drain, if you can stir first, then pour the wort back into the pot to boil, if you need more water do it twice, works great