Mash-out and Efficiency Question

[Jabic]

Greetings,

I've read many conflicting anecdotes regarding the necessary temperature of the water in order to raise the mash-out temp. to 168-170dF. I've heard that a proper mash-out temperature can help improve efficiency as well.

Later today I'll be brewing a recipe; I've been brewing about two years, AG for one year, and I've always fly sparged. Recently I upgrade my system to a 10gal cooler with a bazooka tube and my efficiency has dropped off, about 65%-68% on average (I learned on a friend's false bottom system where efficiency numbers were much better). I am going to try a batch sparge today just to see if channeling is the problem I've been facing.

Anyway, I also want to make sure my mash-out temperature does reach 170dF, as I've never had great luck hitting my mash-out temps and this may be another problem. The recipe will have a total grain weight of 7.56#, and I'll be mashing with a water ratio of 1.4 qt/# - so 2.6 G for mash-in. With losses, I'll be adding 1.1 G for the first sparge addition to hit 2G (half of my preboil volume), and then another 2 G for the second sparge addition to bring my pre-boil total to 4 G.

Okay, so the question is, what temperature should this first sparge addition be in order to come close to that 168-170dF mash-out temp? Or, I would appreciate any sort of advice on how to essentially come to this number. Also, if anyone sees a glaring problem in my batch sparge process, feel free to point it out!

Thanks (and sorry this is so long)!

 

[Sherpa FE]

I recently have upped my eff by using Bobby M's method for sparging. I was still getting 68-72% and then upped my sparge temp to 185 degrees on BOTH sparges and it jumped my efficiency to 80%.

I also use 5.2 ph buffer, and use a finer crush on my grain mill, but through it all, what really helped was the sparge temp.

Try it and see if it helps you.

 

[Joe Camel]

The current mantra as I understand it is that mashout aids flysparging more than batch as it thins the mash and makes is flow a bit more freely.

The one benefit of mashout that will apply to batch sparging is if you want a malty beer. If you don't have two burners so you can't apply heat to your first runnings to stop conversion while heating sparge water, then a mashout will work to denature your enzymes.

You would be better served by doing three things:
1. drop the liquor to grist ratio a bit, maybe 1.2-1.3 qt/lb and save more water for the sparge, this would give you 3.4-3.5 gallons for sparging.

2. drain the first runnings straight into the pot, split the sparge water into two batches, 1.7 gallons each.

3. Heat the sparge water to 180-185F for batch sparging, tannin extraction is not an issue in batch sparging but your extraction efficiency will improve.

 

[oswegan]

I recently did my first batch and my efficiency was pretty low (65-68%). I think my big mistake was adding 170 degree water instead of bringing it up to 170 using hot water like 185. Luckily I was using a ton of grain so I still had a pretty high gravity wort. Next time I am going to bring the mash up to 170 with 185 degree water and let it rest, then I will batch sparge at a temp of 170 by using the hotter water. *Fingers crossed*

 

[Jabic]

I finished the brew a little while ago and, unfortunately, I got my worst efficiency ever: 52%.

Maybe my LHBS has too coarse of a grind, though past batches never went below 64%, so I don't quite know what's up. I'm guessing it is something I'm doing. Grrr!

 

[Reverend JC]

I have never checked temp of the grain bed, but I use 185 water and have never had a prob with eff. or extracting tannins from the grain as a result of a sparge that is too hot.

I fly sparge.

 

[ajf]

I have also recently tried using a 10g cooler for my MLT. (I used to use a 5g cooler).
I found that (using the procedures I used with the 5g cooler) my efficiency dropped by 10 - 15%
With the 5g cooler, Promash always gave me pretty accurate results for the volume and temperature of mash out infusions.
With the 10g cooler, the estimates were wildly inaccurate.
I believe that this is because I have told Promash that my cooler has 0 thermal mass, and I pre heat it before adding my strike water, but when adding an infusion, when the cooler is less than 1/2 full, the thermal mass of the MLT needs to be taken into consideration. (My sparge temperature was in the low 160's.)
I know that with the 10g cooler, I have temperature problems, but I suspect I may also have chanelling problems when fly sparging because of the reduced grain bed depth. See https://www.homebrewtalk.com/f36/channeling-check-fly-sparging-53713/#post541754 for a method of checking this.
What batch size are you brewing? A 4g pre-boil volume seems very low unless you're making 2.5g batches, and I think a 10g MLT may not be efficient for small batches.

-a.

 

[Jabic]

That's an interesting point. I'm not sure I understand the principle of thermal mass, but I'll take your word for it that heat distribution can vary in a larger set up.

I usually brew 3 gallon batches - I draw off 4 gallons of wort and with shrinkage, losses and trub I usually end up near my 3 gallon mark (I'd work with 5 gallon batches, but my kettle just isn't big enough at the moment).

Next batch I'm brewing with a friend and it's going to be a 5.5 gallon batch, and I 'm going to return to a fly sparge technique, so I'll see if I get better efficiency than my standard 65%. Also, I'll test for the channeling problem next time I make a 3 gallon batch.

Just out of curiosity, at what gravity do you write off final runnings? I remember a recent batch where, even after drawing off 4 gallons of wort, my final runnings were clocking in at 1.020. I assume that not drawing off more and extending the boil in this case may have affected my efficiency. Any guiding principles here?

Thanks.

 

[ajf]

I stop when my runnings get down to 1.008 or when I reach my final volume (whichever comes first). They both happen at about the same time. I also sparge for about 60 minutes for a 1.050 OG brew to - 90 minutes for a 1.075 OG brew, but that's collecting 6.75g wort for the boil. You shouldn't need to sparge for as long collecting 4g.

-a.

 

[WBC]

I fly sparge right now and like it better than batch sparge because I get slightly more efficiency and less time stirring during lauter.

If my mash-tun is really full I do a decoction mashout by heating only mash liquid to boiling and adding (while stirring) enough liquid to bring the whole mash to 169F. After that I sparge with 170F water until I have my preboil volume. Expect 85% or more if your grains were crushed well and you mashed properly.

Thermal Mass:
Any object that can retain heat or cold is a mass. To change the temperature of that mass takes energy. If the mass is large it takes a lot more energy per unit of time to change it. Think of heating a small pan of water and then a large one on the same burner on the stove. The mass of the large pot is many times of the small one and it takes a lot longer to boil or cool.

 

[Jabic]

WBC,

Interesting, and it sounds like that would be a good way to bring the mash-out temp to 170dF. What proportion of the runoff do you need to reheat to boiling to bring the rest of the mash to 170? I imagine it is not an exact answer, but if you bring too much to boiling then what do you do with it? Also, do you vorlof the mash liquid you drain off, or do you only do this when you are actually ready to runoff keeping wort?

Thanks.

 

[WBC]

I use Beersmith to figure the amount of liquid so that I have more than enough to reach 169F but there are online decoction calculators too. Below you can see a decoction mash but you can just pick to do the decoction mashout after a normal batch sparge or fly sparge too. I always vorlauf before runoff to buckets or the boil kettle. This was for a 12 gallon batch so I would think half would work for 6 gallons. The grain bill for this one was 23.5 LBS. If you boil too much liquid and do not use it all to heat the mashout it's no problem just add it to the boil pot.

 

[Jabic]

Thanks for the info. Any reason not to use a portion of sparge water to boil? Just curious why use runoff?

 

[WBC]

Thanks for the info. Any reason not to use a portion of sparge water to boil? Just curious why use runoff?

Because you want as much of the sugar as you can get from the mash. If you stop early you are leaving sugar behind. Sparge until you have your preboil volume. Remember to sparge slowly if you are fly sparging. A quart per minute is a good rate.