My efficiency issues continue to trouble me. I am at my wit's end trying to figure out what could be the cause, as I've spent a long time reading about the proper BIAB technique.
Obviously, I am not WAY off, but my inconsistency troubles me. My previous two batches I finally got my efficiency up to around 73-75% which is pretty acceptable to me. However, yesterday's brew was down around 68% following the exact same procedures.
I don't mind adding a pound or so of base malt to make sure I hit my targets, but I really would rather figure out what the problem is rather than work around it. I read all the time brewers talk about getting close to 80% with BIAB.
Yesterday, I made
this IPA. I hit 1.060 as opposed to the target 1.065. Here's my process:
1. Double crush grain at the LHBS.
2. Use a calculator to determine my strike temp and heat water.
3. Pour grain into bag about 25% at a time and stir, until its all in. I hit my mash temp exactly.
4. I always do a 90 minute mash to help efficiency. I stir the grain every 15 minutes during this process.
5. I raise temp to 170F, stir, and allow to rest for 10 minutes.
6. I suspend the bag over the wort with a pulley and allow to drain as I begin heating for the boil.
7. I squeeze the bag until my pre-boil volume is reached. Depending on how much additional volume I need, I may squeeze a lot, or a little, but I've gotten my volumes pretty dialed in.
8. Boil away.
So is there anything glaring during my process that shows why I might have an efficiency be around 68%? I read all the time that brewers say "I give up some efficiency doing BIAB but usually hit the upper 70%'s". I have never achieved this.