Original Gravity question

[mattyg]

Brewed this Centennial Blonde on Sunday:
Did the 11G AG version.

Sparged to 12.7G & boiled down to 11G after 60 min. We lost about a 1/2G to a tubing fail during chilling so we only ended up with about 9.5G split between two carboys (I assume the rest was absorbed by the hops).

We ended up with a much higher OG than what is specified in the recipe: 1.046 vs. 1.038. The only thing that we varied (not intentionally) was mashing at a slightly higher temp (154 vs. 150). Could that account for an extra 8 points? Or is the loss of volume post boil the culprit? Or something else I haven't considered?

 

[TopherM]

The loss of volume wouldn't have changed the OG at all. Gravity is a measure of density, and a uniformly mixed solution doesn't lose or gain denisty no matter how much you dump out...one drop is as dense as 1,000 gallons.

The mash temp MAY have had a small part, but it wouldn't as a general rule change the OG. You get a DIFFERENT kind of conversion at different mash temps (i.e., different sugar and enzyme chemistries/characteristics), but not particularly more or less conversion.

I would think more about your efficiency and all the factors that go into efficiency, like crush, good sparge/mashout or whatever technique, etc.

Did you do any pre-boil gravity readings or otherwise record your efficiency? The recipe assumes 70% efficiency, so if you hit higher than 70%, there's your extra gravity points.

Either way, that spread is not enough to drastically change the characteristics of the beer, so I'd jsut roll with it and enjoy the slightly higher body and ABV!

 

[mattyg]

Even as I was typing that out I was thinking that the density wouldn't have changed with the loss of volume.

Unfortunately we didn't take any pre-boil readings during this batch. I have had 85% efficiency in the past. I didn't notice this recipe assumed 70%...you are probably right. Thanks!

Yeah, I wasn't overly concered about it. Just curious. Overshooting is always better than undershooting.

 

[tre9er]

As a rule I put in a recipe then look at the OG at my target efficiency. I've been using 70% and falling slightly short until recently when I exceeded it by a thin margin. Once I can confirm my efficiency has increased (process has changed) I will use that number going forward and adjust recipes to still achieve the target OG.