No sparge full volume mash and no mash out. Strike water was 156 and went down to 151.8. My target was 150 so I just let it ride. 30 minutes later it was down to 149 so I heated it back to 150 and let it ride till the end.
I suspect I should've added more water. Possibly the mill was set up wrong.
Perhaps when I'm trying to mash so low I need to mash another 15 minutes. That's what I do with the wheat beers.
More water is only a good idea if you are short on your pre-boil volume. Splitting your water to allow for a sparge can improve your lauter efficiency, but it won't help much if your conversion efficiency is low (it's hard to extract sugar from the mash if it's not there to start with.) Inadequate grain crush combined with mash times that are too short are the leading causes of low conversion efficiency. Getting a finer crush is the easiest way to deal will low conversion efficiency with BIAB, as we don't have to worry about stuck sparges. Stuck sparges are what limits how fine traditional MLT users can crush their grains, and HBS's have to crush coarse to keep traditional brewers from having stuck sparges.
A longer mash probably would have helped. At lower temperatures the chemical reactions and diffusion required for saccharification happen a little slower, so more time will let them proceed more towards completion. Also, more time can compensate for a coarser crush. Larger grain particles need more time for the diffusion controlled processes to get to the center of the grain particles. The mash out suggested by another responder is really just an extended mash time with higher temps to accelerate the reactions and diffusion. If a mash out is conducted too early, the amylase enzymes will get denatured before the conversion is complete. Whereas, if you just extend your mash times at normal mash temperatures, conversion will continue without denaturing the enzymes.
There are two ways to monitor for conversion completion. One is the iodine test where you place a sample of your mash on a white surface, and add a few drops of iodine solution. If it turns dark blue or black, then starch is still present. To do this correctly you need to get grains and wort from the mash, and smash up the grains some more before the test. If you test just the wort, often the wort will be starch free, even tho the grain still contains starch, and you will think your mash is complete when it is not.
The other way is to monitor the specific gravity of the wort in the mash. It is possible to calculate the specific gravity you would have at 100% conversion based on your strike volume and your grain bill. In order for this method to work well, you need to be very accurate with your water volume and grain weight measurements. I discuss more about this
here,
here, and
here.
Brew on
