Mash OG = 1.059... after vigorous boil, OG = 1.067

Just wondering how there could only be an eight point change in gravity from mash to post boil.  Any thoughts?

it amounts to about 10 % boil off. maybe a bit short but… if it seems wildly off I would check your instruments!

Hmmm . . . failure to adjust for temp?  Weaker than expected boil?  Shorter than expected boil due to daylight savings?

I boiled the wort (vigorously) for 75 minutes… I lost at least 1 1/2 gallons of water in the boil during that time.  And I waited until the liquid for both was around 70F.  Is 10% boil off average or close to average?  I’m just used to seeing a bigger difference… maybe twice what I got on this brew.  RDWHHB, right?

Was it an 11 gallon batch? I never brew batches that big, but 1.5 gallons of water lost in a 75 minutes boil doesn’t seem like a lot for a batch that big, maybe you did need a more vigorous boil. That being said, 1.067 isn’t that bad, so yeah, RDWHAHB  :wink:

for sure RDWHAHB but also check your instruments cause that math doesn’t work out unless it was a 10 or 11 gallon batch.

if it’s a 5 gallon batch that’s 20% boil off and you should have ended up with 1.082 ish on a 10 gallon 1.5 gallons is ~9% which would be around 1.070

boiled 8 gallons down to just over 6 gallons… the hops soaked up a good bit too.  i was really expecting a higher o.g… strange.

hmm

so 8 gallons to 6.75 is 10% and expected OG of 1.070 which is not out of line with your readings.

Ok… so I wasn’t that far off.  It just seems most of my beers achieve relative higher OG’s than this one.  Either way, it should drink just fine… just a lower ABV than I was expecting.

8 gallons boiling down to 6.75 is about 15%.  Down to 6.25 would be over 20%.

When you say mash OG, I assume you mean in the kettle before boiling and after all sparging?

My guess is that there was some stratification somewhere and one of your measurements is wrong.

That happened to me. I was making a beer and started the boil at 1:59am and it one minute it was already 3:00am?!?! Threw me right off.  8)