Final Gravity = Fully fermented?

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W0rthog

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Yet another newb question.
I goofed when pitching my yeast into an Oktoberfest, because I didn't make a starter. With 1 smack pack, there was lag, but i believe the beer reached the proper final gravity.
My question is this; if a beer reaches final gravity, does this mean it finished fermenting?
My concern is my beer may be too sweet due to low yeast count. I'll know in 2 months when it's done lager'ing.
Thanks in advance
 
"Final gravity" is ONLY determined by when the gravity reading is stable over a few samples taken days apart. Don't ever get it from a number you saw somewhere. Every beer does it's own thing.
 
In short, yes Final Gravity means final gravity or complete fermentation. As tre9er stated, every beer will finish differently as there are a lot of factors involved in a beer reaching its final gravity so just because a recipe tells you it should be 1.xxxx doesn't mean your beer will be there when done. Some may be higher, some lower but if you take a couple samples over a few days and they remain the same then the beer is done.
 
The low yeast count won't affect the final sweetness of your beer, that's determined by the amount unfermentable sugars you have in you're recipe. if your final gravity is supposed to be 1.018, it will be a much sweeter beer than say 1.005. Remember, gravity readings are just a measure of how much sugar is resolved in a liquid.

That being said, an under pitch (low initial yeast count) can give you some off flavors because it initially puts extra stress on the yeast. However, the yeast do do a fairly good job cleaning up after themselves, they'll remove some of the off flavors given time.

If you tell us the OG we'll be able to tell you how badly (if at all) you underpitched. But i wouldn't worry about it, I've never known anyone to do a starter on their first brew.... I've done a few without starters and they've turned out delicious.
 
Are you doing all grain? I found that mashing at the wrong temp made me miss my final gravities in the beginning. Too hot and you'll be sweet, too low and you'll be too thin.
 
"Final gravity" is ONLY determined by when the gravity reading is stable over a few samples taken days apart. Don't ever get it from a number you saw somewhere. Every beer does it's own thing.

How true.
I routinely finish a few points lower that the predicted FG.
 
I'll be honest - I just let mine sit in the primary for 3-4 weeks. I take my gravity reading then. After a month it should be done and I trust the brew to bottles. No bottle bombs after doing it this way for 3 years.
 
Don't confuse done fermenting with done and ready to bottle. Yes you can bottle when it is done fermenting but if you give it a little extra time the yeast will clean up some of the off flavors and you will have a better tasting beer.
 
Matt3989 said:
The low yeast count won't affect the final sweetness of your beer, that's determined by the amount unfermentable sugars you have in you're recipe. if your final gravity is supposed to be 1.018, it will be a much sweeter beer than say 1.005. Remember, gravity readings are just a measure of how much sugar is resolved in a liquid.

That being said, an under pitch (low initial yeast count) can give you some off flavors because it initially puts extra stress on the yeast. However, the yeast do do a fairly good job cleaning up after themselves, they'll remove some of the off flavors given time.

If you tell us the OG we'll be able to tell you how badly (if at all) you underpitched. But i wouldn't worry about it, I've never known anyone to do a starter on their first brew.... I've done a few without starters and they've turned out delicious.

Excellent answer
 
manoaction said:
Are you doing all grain? I found that mashing at the wrong temp made me miss my final gravities in the beginning. Too hot and you'll be sweet, too low and you'll be too thin.

I'm doing an extract kit. Thanks for sharing.
 
Matt3989 said:
The low yeast count won't affect the final sweetness of your beer, that's determined by the amount unfermentable sugars you have in you're recipe. if your final gravity is supposed to be 1.018, it will be a much sweeter beer than say 1.005. Remember, gravity readings are just a measure of how much sugar is resolved in a liquid.

That being said, an under pitch (low initial yeast count) can give you some off flavors because it initially puts extra stress on the yeast. However, the yeast do do a fairly good job cleaning up after themselves, they'll remove some of the off flavors given time.

If you tell us the OG we'll be able to tell you how badly (if at all) you underpitched. But i wouldn't worry about it, I've never known anyone to do a starter on their first brew.... I've done a few without starters and they've turned out delicious.

The OG stated on the extract kit was 1.058, which is what I read on my batch. iBrewMaster states a FG of 1.016, which I read 1.015 on my batch. So I'm thinking I should be ok. I'm also fermenting it for 2 more months at 36 degrees, so hoping any funk gets fixed. :) Thanks All!
 
Matt had the answer for your question, but I have another question. Are you using a lager technique on an ale? What was the kit and what was the yeast used?
 
The OG stated on the extract kit was 1.058, which is what I read on my batch. iBrewMaster states a FG of 1.016, which I read 1.015 on my batch. So I'm thinking I should be ok. I'm also fermenting it for 2 more months at 36 degrees, so hoping any funk gets fixed. :) Thanks All!


2 more months is way over kill. you've already hit your FG, if it's been fermenting for 3 weeks it's had time to clean itself up. My opinion is to knock it down to 36dF for a couple of days (a cold crash, to precipitate a lot of junk out and make clearer beer), then bottle it, let it carb up, and enjoy it.

I don't like the idea of extended lagering temps for an ale, the yeast basically just go to sleep while the temp is that low. And the cold break percipitant you get from a dropping the temp can actually redesolve into the beer so you'll end up with cloudy beer. I've never done it, so don't take my word as law, but I just don't see how it'll benefit you very much. 2 months of lagering an ale = just brew another beer :)
 
oh, my bad.... I completely forgot what the first post said in it when i wrote that... So much for trying to give advice after the bar...
 
ShinyBuddha said:
Matt had the answer for your question, but I have another question. Are you using a lager technique on an ale? What was the kit and what was the yeast used?

I believe the Oktoberfest is a lager. The kit is from Northern Brewer and the yeast is Wyeast 2633 Oktoberfest Blend.
 
Matt3989 said:
2 more months is way over kill. you've already hit your FG, if it's been fermenting for 3 weeks it's had time to clean itself up. My opinion is to knock it down to 36dF for a couple of days (a cold crash, to precipitate a lot of junk out and make clearer beer), then bottle it, let it carb up, and enjoy it.

I don't like the idea of extended lagering temps for an ale, the yeast basically just go to sleep while the temp is that low. And the cold break percipitant you get from a dropping the temp can actually redesolve into the beer so you'll end up with cloudy beer. I've never done it, so don't take my word as law, but I just don't see how it'll benefit you very much. 2 months of lagering an ale = just brew another beer :)

i guess my goal is so that all the byproducts of fermenting mellow out a bit. I'll try it once to see the final product.
Thanks for your time and knowledge :) Cheers
 
You should have some expectations of proper attenuation regarding final gravity. Wyeast will tell you what the attenuation should be for the type of yeast you used. Taking a sample and confirming that you reached the gravity range of that yeast is the best way to determine if the beer has fermented to a proper final gravity. If the yeast did not attenuate enough then steps need to be taken before bottling to prevent overcarbonation due to residual sugars in the beer. This would be the case for ales or lagers. What was your o.g. your f.g. and the type of yeast used?
mark
www.backyardbrewer.blogspot.com
 
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