Missed OG by 11 points

[Dymnas]

Hi,

I brewed a heavily wheat beer a couple weeks ago and missed my OG by 11 points and have been puzzled by it ever since.

Batch size: 5.5 gal
3.3lbs Extra light LME
5.5lbs Light Wheat (Ger)
0.5lbs Light Wheat (Ger) Home toasted
1.5lbs Rye
0.75lbs Flaked Wheat
0.66lbs Rice Hulls

Predicted OG (beer calc) 1.062
Measured OG 1.051

I did a single infusion mash at 154`F for 1 hour, then sparged and recirculated well before adding the LME. The grain was still a little sticky but not crazy.
I'm using NYC tap water, which is very soft. Is this a water hardness issue? It's only my third batch so I'm a little nervous about water salts.
My second batch, a stout, I nailed my predicted OG exactly, so I'm a bit confused as to what went wrong here.

Thanks for your help.

 

[Schnitzengiggle]

Perhaps you over sparged, or over diluted if you added water post boil?

Or you have an extremely crappy Brew House Efficiency of 51%!

 

[ThePearsonFam]

how well was the grain crushed? did you add rice hulls to facilitate sparging? both wheat and rye are huskless and would need rice hulls to properly sparge.

 

[Dymnas]

When I went to brew, I was expecting to do a 5.0 gal batch with a target OG of 1.068.
When I finished brewing, I decided to bump it up to 5.5 gal to account for trub loss, and when I got my 1.051 I thought at least some of it was due to the extra half gallon, but then beer calculus said the same recipe at 5.5 gal should be 1.062. So it's not all of the loss, but it is some.

the grain was milled at the LHBS and it was pretty nice and fine. I did add 2/3rds of a pound of rice hulls to facilitate the sparge.

 

[KevinW]

Did you check for conversion?
Maybe the 1 hour mash is not long enough for full starch conversion!

Just a thought

 

[Schnitzengiggle]

Did you check for conversion?
Maybe the 1 hour mash is not long enough for full starch conversion!

Just a thought

Good point, using that much wheat, and if your Rye was Rye malt, then you should have done an infusion step mash, resting the grain at 122°f for about 20-30 minutes before infusing with enough hot water to bring your grain temp up to the 154°f you initially rested at.

I'm on board with Kevin, you probably didn't have full conversion.

 

[Carter1932]

... you should have done an infusion step mash, resting the grain at 122°f for about 20-30 minutes before infusing with enough hot water to bring your grain temp up to the 154°f you initially rested at.

Agreed. I always do a protein rest on my wheat mashes, which is usually about 45 mins @ 122˚ F.

 

[Dymnas]

Awesome. I'll do that next time! Thanks!

 

[ajf]

When I went to brew, I was expecting to do a 5.0 gal batch with a target OG of 1.068.
When I finished brewing, I decided to bump it up to 5.5 gal to account for trub loss, and when I got my 1.051 I thought at least some of it was due to the extra half gallon, but then beer calculus said the same recipe at 5.5 gal should be 1.062. So it's not all of the loss, but it is some.

the grain was milled at the LHBS and it was pretty nice and fine. I did add 2/3rds of a pound of rice hulls to facilitate the sparge.

If you added water to top up to 5.5 gal, my bet is that you didn't mix the top up water sufficiently with the wort. That would give you an apparent low gravity if you took the sample from the top of the wort, or a high gravity if you took the sample from the bottom.

-a.

 

[Schnitzengiggle]

If you added water to top up to 5.5 gal, my bet is that you didn't mix the top up water sufficiently with the wort. That would give you an apparent low gravity if you took the sample from the top of the wort, or a high gravity if you took the sample from the bottom.

-a.

Another very plausible hypothesis, you guys are freakin geniuses!

 

[Haputanlas]

I always make sure to get a pre-boil gravity reading and calculate what the specific gravity will be after I boil. This allows me to make sure I hit my numbers.

I'd rather boil off more water (less beer) and hit my numbers than end up with a completely different beer.