High FG and poor attenuation

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brelic

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I searched through alot of similar threads but not really sure I got my response.

Essentially I brewed a steam beer and added some flaked corn to the bill to make what I like to call a Steam 'n' Cream.

OG was 1.058, Gravity after 13 days is 1.024-1.025 (@ constant temperature of 62F). Seems much too high for me. AA is 57% using Wyeast 2112 california common (avg. attenuation for this strain is 69%).

The beer is not bad tasting at all. In fact, it's pretty darn nice. However, I don't like the poor attenuation and I'm not sure what I did wrong. Or, rather, I'm not sure which of my mistakes is most responsible ;)

Forgot to heat up the mash tun (converted cooler) as a results, 30 minutes after mash in, noticed that the temp had dropped from an initial 150-151 to about 145-146. Added about 1 g of water to bring the temp back up to 152, extended the mash to 70 minutes total.

So, it wasn't the best mash because I forgot to warm it up.. usually there's hardly any temperature drop. Now I'm thinking the mash wasn't long enough at the right temperature to allow the enzymes time to do their thing.

Secondly, this was the first AG batch where we milled our own grain. Usually with store milled grain, our efficiency hovered between 65-72%. With this batch, it was an abysmal 52%!!! I almost cried. But hey, you gotta learn, right?

How much can grain crush affect fermentability? If anything, I believe our grain was undercrushed.

On top of that, the mash thickness was 1.18:1, until we added the extra water, of course.

To top it all off, because our efficiency was so low, we had to add 1lb of DME dissolved in water just before boil to boost up the gravity.

Overall, not a very 'clean' process. One mistake quickly threw everything off. But it's not the first time our gravity finishes high, and I'm wondering what the likely culprit is. For example, a belgian blonde with 1.061 OG finished just fine at 1.015.

So, it could be the yeast. I did not use a starter. I've never used one, and things turn out fine *most* of the time. In the most recent BYO, a quasi-scientific experiment on pitching rates found that, on average, there is little difference in FG when pitching a certain amount of yeast, 1/4 that amount, or 4 times that amount, all other things being equal (they used the same wort divided in three, same yeast strain, temperature, etc).

Could it be aeration? Following the boil and chill using an IC, we filter the wort through a SS strainer into the ale pail, which already gives it a decent amount of oxygen. Then just before pitching, I stir vigourously for a few minutes or so.

Anyway, maybe I'm making too much of a big deal over this since the beer as it stands now is still quite drinkable and quite nice. I think it's the principle of the matter and the fact that it is likely poor technique that I want to improve.

Any thoughts?
 

JesseRC

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it sounds like you mashed pretty low but still got conversion. I would expect you to end up with a pretty thin beer and low gravity. I suspect you just need to relax and let it sit. 13days is still too soon in my book . I've had a stout go from 1.030 to 1.018 after week 3. What are you ferm temps? Maybe let it warm up a bit and swirl the fermenter to get the yeast going again. I'd still wouldn't check it for another few weeks.
 
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brelic

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it sounds like you mashed pretty low but still got conversion. I would expect you to end up with a pretty thin beer and low gravity. I suspect you just need to relax and let it sit. 13days is still too soon in my book . I've had a stout go from 1.030 to 1.018 after week 3. What are you ferm temps? Maybe let it warm up a bit and swirl the fermenter to get the yeast going again. I'd still wouldn't check it for another few weeks.
Ferm temp has been 62-64 over the entire period so far, and I don't really want to warm it up because it's a lager yeast and so far, it has a nice feel to it.

I figured by now the primary fermentation would be done. Interesting to hear about your stout, though... Hmm.

I swirled the fermenter last night a few times, so maybe that will kickstart it again.
 
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