First session using digimash - for mashing. I brewed an oktoberfest with a target gravity of 1.047 before boil. The recipe, from beersmith, specified 21qts mash water and 8qts sparge water. Sparge went quite quick - too quick in my opinion and I was unable to track the gravity as it went.
I ended up with 1.040 gravity with 7.2 gals. I don't think the sparging went well as the drippings from the malt pipe were quite high in gravity (1.016) after sparge was done. This seems to indicate a 65% efficiency of the mash. I was targeting 76%, not knowing what to expect.
Besides creating a manifold for the sparge and slowing it down, what do others do to achieve reasonable (closer to 80%) efficiencies ?
thx
Couple of questions:
- What was your grain bill?
- Does the Digimash have a malt basket (perforated sides) or malt pipe (solid sides) to hold the grain?
To diagnose your mash efficiency you need to separate out your conversion efficiency (how much of the available starch did you convert to sugar?) and your lauter efficiency (how much of the actual sugar did you get into your boil vessel?). Mash efficiency = conversion efficiency * lauter efficiency. The causes and cures when either of these are low are different, so you have to know which of the two is abnormally low so you know which one needs to be fixed and what might need to be done.
You also need to collect accurate grain weights, water volumes, wort volumes, and SG readings. You should measure the SG at the end of the mash (prior to sparging)
after homogenizing the wort well, as the grain bill, strike volume, and end of mash SG can be used to calculate your conversion efficiency. To calculate your mash efficiency, you need the grain bill, pre-boil volume, and pre-boil SG, or the grain bill, post-boil volume, and post-boil SG. Lauter efficiency is calculated as mash efficiency / conversion efficiency.
You say you mashed and sparged with 7.25 gal (29 qt) of water, and say you collected 7.2 gal pre-boil. For a 10 lb grain bill, that would calculate to a 0.005 gal/lb absorption rate. Since a typical basket absorption rate is about 0.12 gal/lb, at least one of your volume measurements has significant error, and the measurements are inadequately accurate for the task of estimating efficiencies.
So, your first task with your next brew is to make sure you are taking all off the measurements above, and improving the accuracy of your volume measurements (these are usually more problematic than grain weight or SG measurements.)
Brew on