Can some one explain flocculation and attenuation?

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amishland

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This describes the New Belgium Fat Tire Wyeast
Flocculation: low. Apparent attenuation: 73-77%.

What exactly is flocculation and attenuation?

I assume it is how rapid a fermentation can be and how much it can drop the Gravity?

Thanks
 

Yooper

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The actual definitions from howtobrew.com are:

Attenuation - The degree of conversion of sugar to alcohol and CO2
Flocculation - To cause to group together. In the case of yeast, it is the clumping and settling of the yeast out of solution.

Now, what that means in practical terms to us brewers is actually very simple. The attenuation of the yeast is what gives certain characteristics to the beer. Like, if I use a low-attenuating yeast, I will have a slightly sweeter beer. If I use a very high-attenuating yeast, I'll have a dryer beer with less residual sugars left.

Flocculation also has some practical considerations. Some very low-flocculating yeasts make the beer harder to clear. Some high flocculating yeasts might drop out too soon, before the fermentation is even done. If you know these characteristics of the yeast you're using, you'll know how to handle your fermentation, like whether or not to use finings, or to swirl your primary.

You can choose yeasts based on what your plan for the beer is- that's why there is such a great variety.
 

The Soft Underbelly

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using the attenuation percentage, is there a mathematical formula i can use to determine ideal final gravity from the original?
 

brewt00l

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The Soft Underbelly said:
using the attenuation percentage, is there a mathematical formula i can use to determine ideal final gravity from the original?
OG X expected apparent attenuation ...but most people look at it more from the POV of FG/OG and comparing that to the apparent attenuation.

Of course, you have to take into account recipes with large amounts of unfermentables or other conditions what will alter the yeasts ability to ferment to the expected attenuation range.
 

cheezydemon

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That is really too anal for me. But if you want to "NERD OUT" (really no offense intended, where would we be without nerds?)
By all means calculate it out.

For me I figure it is all Beer under the bridge by that point. When it is done, it is done, and your FG is what it is.

Just keep good notes and you will see how which beers reacted with which yeasts.

Good luck! Just remember: It will be beer, regardless of what anything else says.
 

malkore

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The Soft Underbelly said:
using the attenuation percentage, is there a mathematical formula i can use to determine ideal final gravity from the original?
OG (drop the 1.) times apparent attenution. then you take taht value and subtract from the OG.

So an OG of 1.040 is 40. 40 times 70% = 28
40 - 28 = 12

so an apparent attenuation of 70% would mean a beer with an original gravity of 1.040 should finish at about 1.012...assuming the wort is mostly fermentable sugar.
 
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amishland

amishland

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YooperBrew said:
T\

Flocculation also has some practical considerations. Some very low-flocculating yeasts make the beer harder to clear. Some high flocculating yeasts might drop out too soon, before the fermentation is even done. If you know these characteristics of the yeast you're using, you'll know how to handle your fermentation, like whether or not to use finings, or to swirl your primary.

Thanks for the info everyone.

can some one elaberate on yooper's whether or not to use finings or to swirl your primary statement?
 

loopmd

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Finings and the swirling are 2 methods you can use to "clarify" or clear up your beer. Basicly she's saying if the yeasties die before they can ferment all the sugars, you will have various things in your beer to make them cloudy, especially upon chilling your beer. Not that these make the taste any different, just makes for cloudy beer.

Loop
 

malkore

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Swirling is usually done to resuspend some yeast, to reach proper attenuation. Some particularly flocculant strains of yeast will fall out too readily, dragging out primary, unless you swirl a bit.
 

The Soft Underbelly

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malkore said:
OG (drop the 1.) times apparent attenution. then you take taht value and subtract from the OG.

In other words, time to move batch one to the secondary. You guys rock. Thanks for the math lesson!

Nobody EVER told me I would need math to get ahead in this world.
 
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amishland

amishland

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so I wanted to calculate out my math for my phat tyre as of today
I measured [email protected] = 1.015

OG=1.052
ATT=73-77% so this means I should see a drop of 38 to 40

so my FG will be 1.014ish? is my math correct?
 
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