Why are my OG readings higher than calcs?

Hi All,

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
2# Rye
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!

Are you sure your hydrometer is accurate?

Are your volumes accurate?

My hydrometer readings are usually within .001 or .002 of the calculated FG reading, so I'm thinking that isn't the issue and I did hit my volumes for both pre and post boil (4 gal and 3.6 gal)...Wondering if maybe the app assumes a different temperature during hydrometer readings??? Thanks.

Your numbers are wrong. There is no way with the grain bill you posted you have 3 gal of 1.061 wort.

Just because your hydro is close to your estimated numbers doesn't mean it's accurate. Test it in distilled water at 60 F and see what it says.

Did you stir before taking the hydrometer sample?

beerman0001 said:

There is no way with the grain bill you posted you have 3 gal of 1.061 wort.

Click to expand...

Why not? Putting the numbers in Beersmith if he really did hit 90% efficiency he would have that OG. I myself do think something is off, but just saying it's not impossible.


Rev.

I do not have beersmith plugged it in a tastybrew and could not hit that number. Set at 99% it says 1.056. LOL damn I missed the 1# flaked rye. so 89% is 1.061 duh