Mash or Fermentation Problems

[rdude6]

I have made four all grain batches of different styles, three of which have had a higher final gravity than I have hoped for. At this point I dont know whether I need to check my mash routine or the conditions of my fermentation. Any suggestions?

 

[ArcaneXor]

Could be either. Some questions:

What temp have you been mashing at?
Have you calibrated your thermometer?
Do you rehydrate your dry yeast or make sufficiently large starters for liquid yeast?
How do you aerate?
What is your fermentation temperature profile?

 

[rdude6]

I have been mashing at 152 F
My thermometer is currently a meat thermometer calibrated to ice water as 32 F
I aerate by shaking my carboy for about 7 min
My last fermentation was at about 65 F because my basement is cold in the winter. Usually I have a fermentation of about 72 for a week or a week and a half.

 

[ArcaneXor]

Based on your responses, there aren't any obvious problems that can explain your high FGs. One thing to try is to slowly increase the fermentation temperature after the first three or four days, which tends to keep the yeast more active and prevents premature flocculation.
152 is a good middle-of-the-road mash temp that doesn't usually result in sweet beers unless you have a lot of specialty malts in your grist. You can try dropping the mash another couple of degrees to around 150 and seeing if that solves your problem.

 

[ajf]

If you extend the mash time, you will convert some of the unfermentable sugars into fermentable ones, and this will reduce your FG a bit. Since switching to a 90 minute mash at 150F vs 60 minutes at 152F, my FG's have dropped considerably (about 4 - 5 points on average).

-a.