Puzzled about sparging

[Coriba]

I’m puzzled about some of my recent brews.

I’m brewing mostly for whisky wash using 6 lbs two row and 6 lbs peated. I put the grain in twenty litres water at 160 degrees and hold for 90 minutes. I’m using one of those Anvil systems with the grain basket and recirculate periodically. At the end of the mash, I measure the brix before draining at about 16 using a refractometer. Happy with that. I drain the grain and Sparge with four litres water at about 170 degrees. My finished must (wash) is at about 13 brix. A little low.

I tried the same recipe and increased the strike volume to 22 litres and eliminated the Sparge. Again, the brix was 16 at end of mash, but after draining with no Sparge, the brix reduced to 13.

Why do I lose so much after the draining, Sparge or not.

I’ve read quite a bit and can’t figure out what is gong wrong or if this is normal.

Dan

 

[Minbari]

The first one is to be expected. You added water, gravity will go down. But if you don't add water, it shouldn't change. Check your refractometer and make sure your sample cools before you read it.

 

[Coriba]

Yeah, it is that second no Sparge result that caused me to post this question. When I mash, I strike at 160 degrees and it falls over the next 90 minutes to about 145. Some mashing guidelines suggest increasing the temperature at the end to stop some sort of enzymatic activity. Does this make sugar run more freely? Seems like some portion of the sugar is getting locked at then end. I should add that I trust the refractometer.

 

[HighVoltageMan!]

Yeah, it is that second no Sparge result that caused me to post this question. When I mash, I strike at 160 degrees and it falls over the next 90 minutes to about 145. Some mashing guidelines suggest increasing the temperature at the end to stop some sort of enzymatic activity. Does this make sugar run more freely? Seems like some portion of the sugar is getting locked at then end. I should add that I trust the refractometer.

160 is pretty high. You should be more like 145-150 for a whiskey mash to maximize alcohol, high mash temperatures produce a wort that is less fermentable.

The gravity of the mash should remain steady if you are not sparging. If you sparge you should see a drop in gravity but an increase in volume. The extra volume brings with it more sugar. Sparging that much grain with only 4 liters of water seems low, it should be closer to the original amount of water used for the mash. But I make beer and not whiskey.

You really are concerned about overall efficiency and getting the most sugar from the grain. Use the mash efficiency calculator on Brewer's Friend and it will help you determine overall mash efficiency. Typical home brewers hit 75%, some are lower and others are higher. Mash efficiency isn't dependent on one or even two conditions in the mash, it a little more complicated then that. Find out what your efficiency is and take it from there. Use this calculator to get an idea of where your efficiency is landing:

https://www.brewersfriend.com/brewhouse-efficiency/

 

[Donoroto]

The second (13) reading might not be the problem: how well did you stir before the 16 reading? Stratification is a thing.

I also agree 160 is a little too warm. Shoot for 154 max, but 145-150 gives those enzymes room to work ( converting the starches to sugars, then breaking down the complex sugars to simpler, more fermentable sugars). At 160, you get mostly hard-to-ferment sugars, and you've killed the enzymes that you want.

 

[Minbari]

He did say he strikes at 160. It won't stay there with 12lbs cold grain

 

[Donoroto]

He did say he strikes at 160. It won't stay there with 12lbs cold grain

True. But the anvil can make it up in minutes.

 

[Coriba]

Thanks all. I checked my efficiency, about 68%, so not terrible. Just surprised at the drop in brix. Could be stratification I guess. Yes, I strike at 160 and let it fall to 145 in time. I’ll lower my strike temperature and hold at 145 next time. My whisky turns out great in any case. I’m actually shocked I can make whisky so good.

 

[GFHomebrew]

Maybe a tighter crush will lead to more sugars for you and or a longer mash.

Good luck stick with it.

 

[Donoroto]

Thanks all. I checked my efficiency, about 68%, so not terrible. Just surprised at the drop in brix. Could be stratification I guess. Yes, I strike at 160 and let it fall to 145 in time. I’ll lower my strike temperature and hold at 145 next time. My whisky turns out great in any case. I’m actually shocked I can make whisky so good.

I'm happy that it turns out well. If a small change could increase efficiency, that could be good.

If you strike at 160, the grain you are adding will instantly cool the water a bit, to perhaps 152, so maybe I was wrong to suggest a cooler temperature, and @Minbari has it spot on. If you do that and don't add heat to keep it so hot, you are in the right temperature range. I apologize for jumping to my conclusion too quickly.

Do you mill your own grain?
How much whisky comes from a single batch? I am guessing more than a liter, less than four?

 

[Coriba]

Yes I mill my own. I have a hand crank corn mill. The grain looks like all the kernels are cracked and lots of dust. One five gallon batch is about a litre and a bit. It’s a lot of work but a fun and rewarding project.