Batch sparging a large beer

Yes, you would need to add deadspace to the grain absorption. It can have a significant effect on efficiency. So if your deadspace is large your conversion efficiency was probably nearly 100%.

IIRC Kai’s spreadsheet has a separate field for deadspace.

Yes.

I have about 1 quart of deadspace. I took my latest batch numbers and figure my CE was about 82%. My crush gap is set to .039 inches so will lower that to .037 and reevaluate. I also need to see what my mash pH is. One mistake that I know I made was when adding top-off water before sparge #1. I stirred the mash like you would for second running. I believe I should have added and not stirred although I’m not sure what impact stirring would have on my efficiency.

Mark

You want to stir well when making additions - this makes all the wort the same gravity.

Glad you figured out how to use Kai’s calculator to determine Conversion Efficiency.

When you add your top-up water, at the end of your mash, try adding it at a temperature that will raise the mash up in the 158-162°F range for 10-20’ before draining the first runnings. That can help conversion by increasing starch gelatinization, especially with a less than ideal crush.

I read through Kai’s batch sparge analysis and have a question. Assuming a single sparge, one chart says that I would lose about 12% efficiency when going from 11 lbs of grain to 20. Also, when using the wort strength chart the loss is also about 12%. If I’m getting about 70-75% mash efficiency wouldn’t I need to lower my efficiency in Beersmith to 58-64 percent? How did you calcuate the 64-67 number?

TIA,

Mark

What would happen if you did a second sparge… with the first sparge volume? Like double sparging with the same wort?

Since you are actually “rinsing” the sugars from the grains twice, you might get a small increase the second time.

At the end of the mash, the tun is filled with grain plus wort at a single SG, some of which is free to drain and some absorbed by grain. When you drain the first runnings, you are leaving behind wort in the grainbed that is the same SG as the first runnings, so re-sparging with that wouldn’t increase the SG.

Essentially, it would be like trying to rinse soapy water off dishes with the same soapy water.

That sounds about right, but how is it related to what we’re talking about? I thought the question was about moving from a 1.070 beer to a 1.090 beer. 20 lb of grist for 1.090 is reasonable, but to get 5 gal of 1.070 beer from 11 lb of grain, you’d have to be at 90% overall efficiency.

It’s the same calculation I posted before. For a 20 lb grist (2.4 gal absorption, plus .25 gal dead space) and 6.5 gal pre-boil volume:

0.9*((3.25/5.9)+(3.25/5.9)(2.65/5.9)) = 0.72, or 72% lauter efficiency. Multiplying by 90% conversion efficiency gives ~65% overall mash efficiency.

That’s my fault, I looked at the wrong recipe and didn’t bother to correct this thread since your answer was still very helpful. THe actual OG of the first beer was 1.055.

[quote=“a10t2”]It’s the same calculation I posted before. For a 20 lb grist (2.4 gal absorption, plus .25 gal dead space) and 6.5 gal pre-boil volume:

0.9*((3.25/5.9)+(3.25/5.9)(2.65/5.9)) = 0.72, or 72% lauter efficiency. Multiplying by 90% conversion efficiency gives ~65% overall mash efficiency.[/quote]
Yep, I get that. My original beer was 81% lauter efficiency so that’s 73% mash efficiency. In my case, I should lower mash efficiency by 8-10% or so instead of the 12% like above. I guess I was confused as to why the difference between these calculations and Kai’s charts.

That changes things a bit. If you’re getting 70-75% efficiency (~85% conversion) on a 1.055 beer, using the same assumptions as before, you could expect to see 60-64% efficiency on a 1.090 beer.

I’m not sure which of Kai’s charts you’re looking at, but it sounds like it’s giving the change in lauter efficiency due to increasing the grain bill. If lauter efficiency drops by 12% but your conversion efficiency is 85%, then the change in overall mash efficiency is 12%*85% = ~10%.

I agree.

It’s interesting that the simulator says I should get 62.3% efficiency and wort strength of 1.063. Beersmith 2.0 says 1.066. The real difference is the boil off chart. BS says OG should be 1.081 at 15% boil off. The simulator says about 1.075. We’ll see which one is closer. I did enter the weighted average for extract pontential. I also made sure both programs assumed 15% boiloff.

Mark

^^^ This ^^^

Sparge twice, and boil 120 minutes, and your efficiency will be in the 70s. If you don’t, your efficiency will be 60 or less.[/quote]
^^^this

I’d also consider a 3rd and 4th sparge. Boil it separately until u get an OG of 1030, then mason jar/pressure can it for starters. This is my SOP for larger beers. I hate throwing maltose away.

^^^ This ^^^

Sparge twice, and boil 120 minutes, and your efficiency will be in the 70s. If you don’t, your efficiency will be 60 or less.[/quote]
^^^this

I’d also consider a 3rd and 4th sparge. Boil it separately until u get an OG of 1030, then mason jar/pressure can it for starters. This is my SOP for larger beers. I hate throwing maltose away.[/quote]

I did more research on more aggressive and longer boils. Consensus seems to be that both can be detrimental to the beer. A higher boil-off rate can “burn” the wort through the increased thermal loading and a longer boil would coagulate too many of the proteins in the wort which hurts head retention and body. This is from from braukaiser.com.

Also there is the loss of iso-alpha acids in extended boils. The detriments of long boils don’t start happening till after 2 hours and the slope is pretty shallow so you won’t notice much after say 3 hrs.

A 90 minute boil is not “long” by any means. It’s standard if pils malt is used. I’ve made some brews that I boiled for 150 and even 180 minutes that were great with excellent body and head retention.