too high attenuation

I use Wyeast 1056 for most of my pale ales. I typically will use a starter as well, most of the time somewhere in the range of 500ml to 1L depending on the OG.

But I always get much lower FG than I expect. For example, my last batch was an all grain batch with an OG of 1.056. I fermented with a 500ml starter at 68 degrees for 10 days and took a reading. It was at a FG of 1.002 when it should have been somewhere around 1.011 based on beer smith calculations.

What am I doing wrong? Should I not use a starter? Should I remove the beer after 3-4 days from the yeast? Is it my mash? Most of my beers come out tasting fine but I wonder how much better they might be by that little bit of sweetness left over.

Thanks for any help from the forum!

What temperature are you mashing at? How are you taking your gravity readings, and at what temp, and have you calibrated your hydrometer (assuming this is what you're using)?

It sounds as though your thermometer is off and you are mashing lower than you think and getting a much more fermentable wort than you think you are resulting in much greater attenuation.

Odd, I've had the opposite problem a number of times with 3 different yeast strains. Some of mine are a tad too sweet but it seems to mellow out after awhile.

Are you doing extract or all grain? If AG, what's your mash temperature?

Are you brewing all grain? If so mash a little hotter to leave more unfermentables. Also check your thermometer.

Posting the recipe and your procedure might help to diagnose.

As others have said, check mash temp. Also, are you using a lot of simple sugars in your recipe? If so, these will dry it out more.

duboman said:

It sounds as though your thermometer is off and you are mashing lower than you think and getting a much more fermentable wort than you think you are resulting in much greater attenuation.

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I would suspect this first as well.

Calibrate both your mash thermometer and your hydrometer. My first mash thermometer was one of the floating kind. That one read 7*F higher than the actual mash temp. Glad I double checked it.

Thanks all, yes this batch mash was at a lower than desired temp. 150 vs. 152 or even a 154. I have checked my thermometer and it is fine. I even upgraded and bought a research lab grade thermometer from fisher scientific. So for this batch my low mash could explain it but I don't know why my other batches are like that as well.

Should I be mashing at 154 or 155 to try and counteract this?

I am taking my hydrometer readings at room temp. Although my hydrometer is calibrated for 60deg the difference in readings between 60 and 75 is minimal according to their calculations.

I think what was implied by a low mash temp was somewhere around 145 if you were aiming for 150. 150 should give you an average fermentability.

Have you checked you calibrated your hydrometer? It is entirely possible that you could have issue on that side of the equation...

wailingguitar said:

Have you checked you calibrated your hydrometer? It is entirely possible that you could have issue on that side of the equation...

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This. You are not getting 96% efficiency unless your recipe is mainly sugar.