Do non-fermentables contribute to gravity?

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Jacktar

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Brewed an AG stout using s04 yeast. OG: 1054. It's only been 3days and the krausen has dropped and bubbling has slowed waaaaay down. Is this just the character of the yeast burning through my sugars or is it possible there were not many fermentables in that 1054 to begin with? I'll do a gravity reading in a few days to be sure, but any thoughts on this?


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ianw58

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First, 3 days is a decent length for active fermentation.

Second, yes. Non-ferment ambles contribute to gravity.

Gravity is a measure of the total density of a solution relative to water. Pure water has a density of 1. Your wort started "life" 1.054 times as dense as water.
 
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Jacktar

Jacktar

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I usually use us05 and it normally takes much longer than this. I'm curious to see how dry this beer will go.


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rodwha

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US-05 has a slightly higher attenuation than S-04 (~6% more).
 

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Second, yes. Non-ferment ambles contribute to gravity.
Relative to fermentables, how much do the non-fermentables contribute to gravity?

I made a stout recently - the gravity of the mash (at 65 C) was about 1.065. Then I sparged for 10 minutes at 70 C and the gravity of that was about 1.025 - I was hesitant to mix runnings from the sparge in with the first runnings!
 

ianw58

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Relative to fermentables, how much do the non-fermentables contribute to gravity?

I made a stout recently - the gravity of the mash (at 65 C) was about 1.065. Then I sparged for 10 minutes at 70 C and the gravity of that was about 1.025 - I was hesitant to mix runnings from the sparge in with the first runnings!
Just the same as fernentables.

If you dissolve 100 grams of anything in 1000 grams of water, the resulting solution will weigh 1,100 grams and be 1.100 times as dense as water. It doesn't matter whether the material is fernentables sugar or salt. It's simple physics.

The measure of fernentables versus non-fermentables is a far more complex chemical analysis that isn't possible in most home brewery set ups.
 

Yooper

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Relative to fermentables, how much do the non-fermentables contribute to gravity?

I made a stout recently - the gravity of the mash (at 65 C) was about 1.065. Then I sparged for 10 minutes at 70 C and the gravity of that was about 1.025 - I was hesitant to mix runnings from the sparge in with the first runnings!
I"m not sure where the 'nonfermentables' come from- maybe you added lactose or something which isn't fermentable by brewer's yeast- but mash temperatures play a role in the fermentability of the sugars from the mash. A warmer mash temperature generally means more long-chained sugars, and they are not as fermentable as simple sugars. It's not that they become "unfermentable"- they just are less so than sugars produced from a lower temperature mash.
 

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I"m not sure where the 'nonfermentables' come from- maybe you added lactose or something which isn't fermentable by brewer's yeast- but mash temperatures play a role in the fermentability of the sugars from the mash. A warmer mash temperature generally means more long-chained sugars, and they are not as fermentable as simple sugars. It's not that they become "unfermentable"- they just are less so than sugars produced from a lower temperature mash.
It was an all grain. I hoped - wrongly reading Ian's response - that the higher mash/sparge temperature produced a lower gravity wort because of the alpha amylase. I think less sugar (of all kind) was extracted.
 
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Jacktar

Jacktar

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Yooper has gotten to the heart of my question. I was wondering if my wort had finished up initial fermentation quickly because of these long links. I did mash at a pretty high temp, 156-58, so would this mean a sweet beer with a lot of gravity points being left by the yeast bc they are hard to ferment? As I said, I won't know for sure until I do a gravity reading.


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kombat

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I think your fast fermentation is more a product of the yeast strain selected than your wort composition. In my experience, S-04 is a notoriously fast fermenter. The first couple of times I used it, I was afraid I'd screwed up and let the temperature get too high, because after just 2 days, the krausen fell and by all appearances, it looked done. However, the beers turned out fine, my temperatures were normal, and it seems S-04 is just a really quick worker. I wouldn't worry if I were you.
 
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