After completing our second partial mash recipe I re-visited our first and have some questions about procedure and resulting efficiency issues and appreciate your insight:
Recipe:
3lbs 8oz Pale 2-row
8oz carapils
8oz crystal 40L
3.3lbs Pale LME
1oz Chinook 60 minutes
1 oz cascade 15minutes
1oz cascade 2 minutes
Wyeast 2112
Est. OG 1.048
Actual OG 1.040
Measured FG 1.010
Measured efficiency 50.8%
Single infusion 2-step batch sparge
Mash in 5.63qt @172.5 degrees
Step @156 degrees
2 step at 2.26 gallons @156 and 3.13 gallons at 156 degrees
Mash tun is a 5 gallon industrial Bev cooler with a screen, no false bottom
My supplier provided the crushed grains and they appeared to be done fine enough but not so fine to create a lot of dust so I am not sure that can be improved.
First question is regarding pre-boil reading. Is this done prior to adding the extract or after as with extract brewing we never did this and the extract was usually added once the water came to a boil (We do full boils)?
Second Question: Top off water, after the complete mash out we had only 5 gallons. Our system requires 6.25 gallons for a full boil with 1.15 boil off. Should I be topping off the volume prior to the boil and before or after the extract add or should I be boiling everything and then topping off the primary to arrive at the 5 gallons?
Third question: If the pre-boil reading is lower than expected how do I know how much DME to add to get to the expected gravity, is there a general rule of thumb like 1lb per 5 points for example?
For our second batch I just added a lb of DME to the boil because I just assumed from this recipe we would be well off. As a result we actually wound up being high on the OG. While I know this is not an exact science I also know that I shouldn’t just be grasping at straws and guessing either, appreciate your help!