Going over max attenuation

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CreekBrewery

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Since I'm a noob I had to ask about something I'm seeing in my latest beer.
I made a tripel using asome Wyest 3944 I had in the freezer and its attenuation range according to the website is 72-76".

OG = 1.060 (I know this is low, I messed up my first partial mash :mad:)
Then added 1.5 Lb of sugar in three seperate additions so if I'm calculating this correctly... 46*1.5/5.25 = 13 points
So I'm using 1.073 as my OG.

I just took a gravity measurement, she's still bubbling slowly, and it came out at 1.015 with temp corrections. This is where it gets weird because this would give me an apparent attenuation of 78.3% (according to BeerSmith).

Is the website spec just an average range or is something else going on? I did use Mr Malty to calculate my starter size so I know it had a healthy start. Thanks for the help!
 
Apparent attenuation is given for yeast in a wort that has a normal sugar profile (meaning standard mix of fermentable/unfermentable sugar). Your wort did not have that since you added a lot of table sugar which is completely fermentable. Whenever you add sugar, yeast are always going to gobble that up.
 
OK, so are there really any guidelines when you're using a non-standard sugar profile? Does it just come down to how much alcohol the yeast can tolerate at that point?
Thanks, I figured I was just being a nervous Nelly since I'm still learning.
 
You can get an idea of what will happen if you just assume all of your table sugar gets fermented. If you hadn't added table sugar, you would have expected your FG to be about (1-0.74)*60 = 15.6 points (assuming 74% attenuation). Since you expect the extra 13 points to be completely converted into alcohol, you would expect to see a reduction of a point or two in FG due to the effect of extra alcohol on density. So, I would expect you should've seen 14-15 points in the end, which you did.

You are right...this process is limited by the alcohol tolerance of the yeast. Just because you have %74 percent attenuation listed on the package doesn't mean your 1.200 wort will go down to 1.052 if your yeast poop out at 10% alcohol. You would rather expect it to finish around 1.124.
 
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