Preboil gravity low. Why?

kristophelr · 10-13-2011, 08:18 PM

I followed Beersmith instructions exactly for all grain oatmeal stout. Estimated preboil was 1.058 actually measured at 1.031. What happened? Any suggestions?

kristophelr · 10-13-2011, 08:24 PM

Recipe might help
8.5 lbs pale malt (2 row)
14 oz oats
11 oz victory malt
10.5 oz chocolate malt
7 oz crystal 90L
7 oz black barley

Mashed at 154F for 45 min then batch sparged at 168.

**Paul07293** · 10-13-2011, 08:36 PM

Could be a number of factors. Do you normally get better efficiency? What type of lautering system do you have? Most mashes go at least 60 min, why did you do only 45? Are you sure your scale, thermometer and hydrometer are accurate?

kristophelr · 10-13-2011, 09:25 PM

Yes all are accurate. Positive of that. Beer smith said do a 45 minute mash. I'm going to do 60 next time. OG into ferm. ended up being OK 1.052 instead of estimated 1.058. I think beer will be OK.

**TromboneGuy** · 10-14-2011, 02:06 AM

Did you just sparge too much and end up with a way higher volume than expected?

**BrewKnurd** · 10-14-2011, 02:12 AM

Quote:

Originally Posted by kristophelr

Yes all are accurate. Positive of that. Beer smith said do a 45 minute mash. I'm going to do 60 next time. OG into ferm. ended up being OK 1.052 instead of estimated 1.058. I think beer will be OK.

1) pre-boil and og were supposed to be the same? I guess you were topping off with extra water post-boil?

2) when did you take pre-boil gravity? I usually wait until a couple minutes into boil to ensure mixing.

kristophelr · 10-14-2011, 03:00 PM

I thought gravity increased as you boiled due to boil off of water. Thought that was one of the reasons for boil.

**NochEineMassBitte** · 10-14-2011, 03:05 PM

Quote:

Originally Posted by discnjh

when did you take pre-boil gravity? I usually wait until a couple minutes into boil to ensure mixing.

+1 to this.
You gotta give it a good stir or give it time to mix before taking a gravity reading. I've had as much as a 10 point difference in readings before and after mixing.

Also, I've found that my efficiency has really improved since moving to a 75 minute mash. Might just be my system, though. 45 minutes seems a bit on the short side.