This weekend I did two brews, one was a India Red Ale and the other a Delerium Tremens clone. I’ve made both recipes before without issue. But, this weekend BOTH of my pre-boil gravities came in well below what they should have been (46 instead of 56, and 40 instead of 46). I batch sparge, and like I mentioned, batch sparging both of these recipes previously has been fine. Also, my infusion temps were hit exactly at 153 for the IRA and 146 for the DT clone. Temp checks at the end of each mash confirm the temps stayed constant the whole time.
I can only think of two possibilities for the low pre-boil gravities.
Maybe the pre-set mill at Northern Brewer here in Milwaukee was off and I didn’t get a good crush. It looked ok, and I’ve used that same mill before without trouble, but who knows? Anybody in the Milwaukee area have a similar experience with NB?
I usually store my crushed grain until use in a chest freezer with a temp control at 40 degrees, but this time I accidentally left the temp probe outside of the freezer. So the grain froze then I thawed it by leaving it at room temp overnight before I used them. Grain temps were 52 degrees when I mashed in, and I adjusted mash water temp to ensure I hit my mash temp. Could freezing the crushed grains cause this kind of a problem?
I’m going to say no to the freezing alone. My grain is stored in my shop with temps ranging from 100+ to -20. There are times when my grain is below freezing for over a month. All uncrushed of course.
Did you weigh it out? If both were off by the same amount I might suspect that the scale was not adjusted for tare. But they are not so my next suspect is that someone forgot an ingredient maybe… Did they have a common ingredient but different amounts in each?
That’s a good point, I hadn’t thought about the scales being off. I doubt I missed an ingredient because I would have had to miss it twice. Plus, the grain bill for the DT clone is only 13.75 lbs of Belgian Pilsner, so nothing really to miss there.
I did have a fleeting feeling as I was mashing in that the bags of grain seemed lighter than normal, but I attributed it to working out the last few months. ;D I should have checked the weight on my home scale to be sure, but maybe the tare cancelled out while I wasn’t looking and the 3 lb bucket got included in my grain bill resulting in the reduced efficiency.
I just recalculated my preboil based on each grain bill, but subtracting the weight of the bucket. I hit my target exactly if the tare failed and included the weight of the bucket as I put my ingredients together. Dammit. In 10 years of brewing that’s a new problem I’ve never had before. Mystery solved
You’re welcome. I have some experience with "What happened " and I’m a big fan of Occam’s Razor, the solution with the fewest or simplest assumptions is usually correct.
I just recalculated my preboil based on each grain bill, but subtracting the weight of the bucket. I hit my target exactly if the tare failed and included the weight of the bucket as I put my ingredients together. Dammit. In 10 years of brewing that’s a new problem I’ve never had before. Mystery solved 