Just brewed a 3 gallon batch of roggenbier yesterday and had a question on OG...It seems that I'm hitting a really high pre-boil efficiency as well as coming up with a higher than estimated OG (post boil) and am curious as to why...Below is my recipe...I'm using a brewmaster Ap for the iPhone for calculations...
3# 2 Row Pale Ale
1# Flaked Rye
1/2# rice hulls
.25oz Fuggles (4.2%AA) at 60, 45, 30, and 15 minutes
3t yeast nutrient @ 15m
1t irish moss @ 15m
Wyeast American Ale 1056
Process for this batch was as follows:
3gal water strike temp of 163...Measured temp of 150 in Igloo. Mashed 90 min. 2 gal sparge water at 170. Calc'd a mash tun loss of .25 gal and grain absorption of .75 gal. for total of 5 gal into mash and 4 gal for boil. Pulled exactly 4 galls, so that worked OK. Figured I'd lose about 0.6 gal during 60 minute boil and another .25 or so to trub when I rack for a total batch size of about 3 gallons, which is a perfect amount for me and gives me a reason for experimenting more often
My hydrometer reading for my pre-boil was 1.048 (at 60F exactly) versus calculated pre-boil of 1.040, backing into the efficiency, this means I pulled an 89% efficiency during mashing.
So, I adjusted the app's efficiency to 89% which showed my post-boil OG would be 1.054. My hydrometer reading of the post-boil (at 70F) was 1.061.
So I'm guessing my 90 min mash is probably helping out alot with my efficiency, along with a fairly fine grain crush (I use a Barley Crusher set at factory setting of .039) to get me an efficiency higher than the usual 75% standard.
Where I'm a little more confused is on the post-boil OG. Am I pulling in a higher OG reading due to a lower mash temp? I meant to hit a mash temp of 152, but my igloo was a bit cooler from being out in the garage. As I understand it, a lower mash temp will yield more fermentables and result in a thinner beer with more alcohol, so maybe this is the reason behind the higher OG, or am I missing something?
Thanks in advance for your inputs! Cheers!