Does high mash temp cause bad eff?

My last All Grain batch only yielded 65% efficiency.

When i mashed in, my temp was definatley high (at 160) for about 10-12 minutes. I stirred and added ice until I could get it down to 153. Im using a 10 gallon cooler (MLT) and it held 153 for the entire hour. I mashed out with about 8 quarts of boiling water, then sparge with about 3.5 gallons at 185. I also put a TBSP of ph Buffer 5.2 in the mash, and stirred alot. I dont think its a bad grain crush because my LHBS is also Ballast Point, and they were going to be crushing their grains later that night for their commercial beer.

Should I just accept 65% as my efficiency?

I'd say no. You may have destroyed some of the enzymes that convert starch to sugar with those high temps, even for ten or twelve minutes... and I know the infusion mash in a cooler often requires the occational addition of boiling water, but that will also kill off those enzymes- at least where the 200+ temp water hits the mash.

I know a lot of folks out there make great beers with that system but may not be concerned with efficiencies in the eighties or nineties...

-p

I thought I'd add this... the temperature of your srike water depends on your target temp and the temperature of the grain. I've found (though I have no mathematical formula to back it up) that if my grain is 70 degrees (i.e. stored indoors overnight before brewing) and I strike with 156 deg water, my resulting mash is 150 deg. Perfect for the drier ales I like to brew. It seems to work for both 5 and 10 gallon batches...

Cheers, -p

Don't be concerned about temp drops in a cooler. If you hit your target temp it shouldn't drop more than a couple degrees

At 160F, you completely de-natured the beta amylase. Then you dropped the mash temperature below the optimum range for alpha amylase. Just accept 65% for this run.

[Add pH 5.2 to the water before adding it to the mash or mix it with a quart or two of water if you forgot it initially.]

Thanks for all the feedback.

Im still getting to know my equipment, so next time i should come alot closer to my target temp. I discovered a thermometer that was WAY off during this run, and it has been retired.

Your mash temperature will have little or no effect on your efficiency unless your actual mash temp was significantly above 160 for an extended period of time. The big effect will be on the fermentability of the wort. You will have denatured a majority of the beta amylase enzymes which break down the long chain sugars into the shorter chain sugars that the yeast can use.

I would still suspect the crush for a majority of the efficiency problem as mash systems will vary in the crush they work best with. Cooler sytems with braid can handle much finer crush than commericial systems. Commercial systems also use extended recirculation in their mash which helps them to achieve higher efficiency with a coarser crush than what homebrewers typically achieve.

I use a rectangular cooler with SS braid and consistently get efficiencies in the 75-80% range using batch sparging. I typically get a temperature drop of less than 2° during a 60-90 minute mash. If you are using the cylindrical cooler system in a batch sparging situation, you will have more problems with the mash due to the deeper grain bed. 65% efficiency is not all that bad if you are relatively new to all grain. There are all sorts of small treaks that will incrementally increase your efficiency but these will take time to figure out and none of them will make a dramatic increase other than maybe a finer crush.

Wayne
Bugeater Brewing Company