OG too high and FG consistently too low

[yourlastchance89]

I've been brewing about 9 months now and have done about a dozen or so all-grain batches with BIAB? Every single recipe I've done my efficiency has been 75%-80% which I'm fine with, but my beers always finish lower than the the expected gravity. Here's some details from my latest which is a smoked porter.

At 65% efficiency gravity was projected at 1.065 and I got 1.073.
I do a fine crush with a corona mill on the tightest fitting.

Mash was at 154°F for 1 hour which I held in range the whole time.

I pitched Wyeast Thames Valley utilizing a decanted starter with a population goal of 300 billion. Don't know if pH is a factor, but measuring with a pH meter I had a mash pH of 5.4.

8 days later she's sitting at a FG of 1.010.

All my brews have finished this way, which isn't too bad, but they all end up with a drier finish than what is anticipated. Any recommendations?

 

[ProblemChild]

mash temps?

 

[AkTom]

Maybe your crush is too fine?

 

[yourlastchance89]

154 for 60 minutes, which was held consistently the whole time. I also forgot to mention I use 2 different thermometers with both reading the exact same and my hydrometer is calibrated

 

[RM-MN]

My theory is that with a coarser crush you have more control over the fermentability of the beer because it takes more time to gelatinize all the starches. During that time both enzymes start to work but by the time the last of the starch is available the beta amylase enzyme is mostly denatured so you get a less fermentable wort and thus a higher FG. With the very fine milling of your Corona mill the starch gelatinizes very quickly and both enzymes attack it at once, completing conversion before beta amylase can be denatured.

You can try to prove this theory by loosening the setting of your Corona so you get bigger grain particles. However, there is a trade off in that the coarser milling will bring down your mash efficiency and the only way to bring it back up is to go to longer mashes. You might be able to get close to the efficiency you now enjoy by mashing for 90 to 120 minutes.

Your pitch rate may also have influenced the final gravity.

 

[RM-MN]

154 for 60 minutes, which was held consistently the whole time. I also forgot to mention I use 2 different thermometers with both reading the exact same and my hydrometer is calibrated

With your Corona mill set really tight, your conversion didn't take 60 minutes so you effort of keeping the temperature stable for that long was for naught. Your conversion was done in less than 10 minutes.

 

[yourlastchance89]

With your Corona mill set really tight, your conversion didn't take 60 minutes so you effort of keeping the temperature stable for that long was for naught. Your conversion was done in less than 10 minutes.

I was curious if this affected it. Should I gap it wider or should I set my mash durations for a shorter amount of time?

 

[RM-MN]

I was curious if this affected it. Should I gap it wider or should I set my mash durations for a shorter amount of time?

Your choice, plus you can continue to mash for 60 minutes with the crush you have. I do not recommend mashing for less than 30 though as it takes time to leach the flavors out and if you mash too short you get flavorless beer.:rockin:

 

[Sadu]

I have had this problem in the past. Now I will add water to the brew if I overshoot OG by more than a few points. I find that if you want a 5% beer and you get a 6% beer, that is not the same thing and on something like a German lager it becomes less drinkable. Being 1% high on a Belgian blond makes it super boozy and wrecks the character.
Try mashing a bit higher, using a less attenuative yeast (wyeast 1450 is my goto when I don't want a dry beer) and water it down if your OG is too high.

 

[canehdianman]

Mash higher.