Pre-boil gravity good, post boil not.

[beervoid]

Hey all im working with an Ace / Klarstein setup and im trying to dial in my efficiency.

After some tweaking I finally hit my pre-boil gravity as predicted by beersmith (1.053) but after boiling for 60 minutes my gravity was only 1.062 instead of the aimed for 1.072

My efficiency is now about 60% whereas before when I didn't hit my pre-boil gravity I had an efficiency of 68%
The only thing I've changed so far is milling smaller.. (bit bigger then creditcard size)

I changed my mill to mill a bit smaller so I was expecting to hit a higher overal gravity.

Anyone here can help me out what I should be finetuning?

Cheers!

 

[kh54s10]

It would have to be that 1) there was an error in your preboil gravity reading. 2) you didn't boil off nearly as much water as was expected. (wrong volume into the fermenter) 3) you got the right preboil, right volume and bad OG reading.

One of those three or a combination.

Have you worked on your equipment profile in Beersmith? You have to have the right parameters there to have a proper outcome.

 

[shanecb]

1.053 to 1.072 seems like a pretty big jump (at least it would be on my system). Your boil off rate may be set incorrectly. Can you see what that's set as in the equipment profile? That may need some tweaking.

 

[mongoose33]

If you started with 6.5 gallons and boiled down to 5.5 gallons, I would have predicted your OG (postboil) to be....6.5/5.5 * 1.053 = 1.0626. In other words, right where you should have been. Assuming the starting and finishing volumes.

Something wrong w/ your calculator, or something wrong w/ the preboil reading, or you didn't boil off enough. Or something.

 

[beervoid]

I also think my boil was perhaps not good. At the moment it's set to 2.5 liters per hour boil off. (I took the equipment settings from a forum that uses this machine)

I calculated how much water I would need to boil off to hit the right OG and it came to about 1.9 liters.. no coincedentially my Trub/Deadspace is set to 1.8L could this be the culprit as well?

Wouldn't I end up with higher preboil gravity if I remove the trub/deadspace?

I was aiming for 4.5 gallons as I ferment in keg and when filling the keg it seems to me im getting more then 4.5 gal (17 liters)

thanks everyone!