ballantynedewolf
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I asked a yeast retailer this question, but they weren't able to answer. I know what attenuation is. Final gravity sounds like it might be alcohol tolerance?
Why do SAF packets have "final gravity" or "attenuation" but never both?
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theSeekerr
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So far as I can tell it's the same thing as attenuation, just flipped around the other way. High attenuation -> Low Final Gravity, Low attenuation -> High Final Gravity.
What "low" and "high" mean here, I have no idea. Much prefer brands that give estimate apparent attenuation as a percentage range...
What "low" and "high" mean here, I have no idea. Much prefer brands that give estimate apparent attenuation as a percentage range...
The industry is moving away from giving attenuation as a percentage, largely because it isn't all that helpful.
There is a standard test for attenuation and the % values are pretty good at telling you how the yeast will do at the test.
Where it gets problematic is in a wort, its nearly impossible to tell from the test value how the yeast will preform in the real world. True yeasts that attenuate highly in the test tend to attenuate well in a wort, but not maybe the i.e. 80% apparent given in the test.
In effect its the same answer but it saves people sitting around waiting for the yeast to reach some number that it may never achieve in that wort, or may even exceed.
As a general rule, yeasts that attenuate well don't settle quickly and visa versa.
Lager yeasts tend to attenuate better than do Ale yeasts (they can eat some extra sugars)
If you need to know where the beer is going to finish, do a force test (small amount of wort with a lot higher pitch rate or run warmer (or both)). It will finish well before the main brew so if you are racking, planning yeast drops or bunging to carbonate you will know when to act.
Alcohol Tolerance, is the upper limit of alcohol that a given yeast can produce, even if it still has food. there might be enough sugar to make 12% ABV beer, but if the yeast cant cope with more than 10% ABV it will stop at 10% (alcohol is poisonous to yeast to).
Final Gravity, is the lowest value that a given yeast will produce in a given wort (i.e. 1.010)
Alcohol Content, can be calculated (approximately) by taking the change in gravity (OG-FG) in points (1.050 is called 50 points, 1.010 called 10 points) divided by 7.5. So the ABV would be 50-10 = 40, 40/7.5 = 5.333%ABV
Mark
There is a standard test for attenuation and the % values are pretty good at telling you how the yeast will do at the test.
Where it gets problematic is in a wort, its nearly impossible to tell from the test value how the yeast will preform in the real world. True yeasts that attenuate highly in the test tend to attenuate well in a wort, but not maybe the i.e. 80% apparent given in the test.
In effect its the same answer but it saves people sitting around waiting for the yeast to reach some number that it may never achieve in that wort, or may even exceed.
As a general rule, yeasts that attenuate well don't settle quickly and visa versa.
Lager yeasts tend to attenuate better than do Ale yeasts (they can eat some extra sugars)
If you need to know where the beer is going to finish, do a force test (small amount of wort with a lot higher pitch rate or run warmer (or both)). It will finish well before the main brew so if you are racking, planning yeast drops or bunging to carbonate you will know when to act.
Alcohol Tolerance, is the upper limit of alcohol that a given yeast can produce, even if it still has food. there might be enough sugar to make 12% ABV beer, but if the yeast cant cope with more than 10% ABV it will stop at 10% (alcohol is poisonous to yeast to).
Final Gravity, is the lowest value that a given yeast will produce in a given wort (i.e. 1.010)
Alcohol Content, can be calculated (approximately) by taking the change in gravity (OG-FG) in points (1.050 is called 50 points, 1.010 called 10 points) divided by 7.5. So the ABV would be 50-10 = 40, 40/7.5 = 5.333%ABV
Mark
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