Question aboutfermentation times and final gravity

[Brewnoob6120]

I checked the gravity on my batch of "Dark Brown Honey" i'm using single stage fermentation, it has been in the fermenter for 10 days, my targer FG was1.019 my reading today was 1.015, my target OG was 1.070 and my measured OG was 1.065, does this mean that the beer is done fermenting? and I also read different places that higher gravity beers will take longer to ferment, is this correct? and the ABV is 6.53%, does this all sound right?

Dave

 

[Yooper]

How did you arrive at a target FG? If you used some software, that "target" is useless- it's just 75% of the OG or so. FG is a result of many things, such as yeast strain, recipe, and mash temp.

If you mashed under 152, used an attenuative yeast strain, and used simple sugars (such as honey), you could get 85+% attenuation. If you mashed at 156, used a less attenuative yeast strain, and used more crystal grains, then you could get 63% attenuation. That FG in the first example could be 1.008, while the FG in the second could be 1.022.

So, in short, the whole recipe is what decides FG not an arbitrary number from some software. If the beer is done fermenting, the SG will be the same three days later. That's the only way to really know when it's done.

 

[Brewnoob6120]

I mashed at 152, used so4 yeast and yes there was 1# of honey added to the last 10 minutes of the boil, so the numbers that Beersmith churns out are nothing more than a pecentage of the style of beer?

 

[o4_srt]

I mashed at 152, used so4 yeast and yes there was 1# of honey added to the last 10 minutes of the boil, so the numbers that Beersmith churns out are nothing more than a pecentage of the style of beer?

A percentage of your OG. I'm brewing a cream ale tomorrow, jamil's recipe, and I should get around 1.005 or so FG. Beersmith is saying 1.015. Software does not consider wort fermentability, just average attenuation of the yeast strain uses.

 

[Brewnoob6120]

ok I did some checking and so4 yeast is said to have 73% attenuation, I followed the formula on White Labs website [(OG-FG)/(OG-1)]x100 and I came up with an attenuation % of 76.9, so does this mean that the yeast has done it's job? should I bottle it now? and if I don't and the yeast consumes more of the sugars will that effect the taste and body of the beer? sorry about some of the lame questions. This was my first AG brew and just want it to be the best it can

Thanks Dave

 

[o4_srt]

ok I did some checking and so4 yeast is said to have 73% attenuation, I followed the formula on White Labs website [(OG-FG)/(OG-1)]x100 and I came up with an attenuation % of 76.9, so does this mean that the yeast has done it's job? should I bottle it now? and if I don't and the yeast consumes more of the sugars will that effect the taste and body of the beer? sorry about some of the lame questions. This was my first AG brew and just want it to be the best it can

Thanks Dave

Give it a solid month in the primary before bottling. Unless it's a high OG or fruit beer. Fermentation might be complete, but the yeast still has to clean up the mess it made.

I don't even check final gravity with most beers until bottling day simply because I don't want to risk infection.

 

[Yooper]

ok I did some checking and so4 yeast is said to have 73% attenuation, I followed the formula on White Labs website [(OG-FG)/(OG-1)]x100 and I came up with an attenuation % of 76.9, so does this mean that the yeast has done it's job? should I bottle it now? and if I don't and the yeast consumes more of the sugars will that effect the taste and body of the beer? sorry about some of the lame questions. This was my first AG brew and just want it to be the best it can

Thanks Dave

You'll want to wait at least a couple of weeks to make sure it's finished, conditioned a bit, and clearing. When the SG is not moving over at least three days, the active fermentation is over. But the yeast is still working- after the fermentable sugars are gone, the yeast actually go back and digest their own waste products. This is crucial for a good beer- don't touch it for at least two weeks.

When two weeks have passed, and the SG is not changing after at least three days, then it's safe to bottle. Bottling it before fermentation is over will not only give poor tasting beer, but can cause bottle bombs.

To fix body and taste issues, that's a function of the recipe. If the recipe is good, and the ingredients are good, the beer will have good taste and body.

 

[Yooper]

ok I did some checking and so4 yeast is said to have 73% attenuation, I followed the formula on White Labs website [(OG-FG)/(OG-1)]x100 and I came up with an attenuation % of 76.9, so does this mean that the yeast has done it's job? should I bottle it now? and if I don't and the yeast consumes more of the sugars will that effect the taste and body of the beer? sorry about some of the lame questions. This was my first AG brew and just want it to be the best it can

Thanks Dave

Again, that's the average attenuation in an average beer. But honey is 100% fermentable (or nearly so) and will skew that attenuation rate. A finished beer is only finished when the SG is stable, not when an arbitary number is reached.

 

[Brewnoob6120]

ok, I think it's starting to sink in, the attenuation of the yeast is important to know because it gives you a set of guidelines to work from, and the only way to know if it is done fermenting is when the SG becomes stable. and to think I just wanted to brew beer! who knew! just kidding thank you all again!

Dave

 

[malkore]

I have to say that calculating a final gravity estimate is NOT a wasted, useless idea.

Its certainly not a hard line drawn in the sand, but if you estimate the FG (based on yeast used and how you mashed) and come to a number like 1.015...adn then after 3 weeks your stout is at 1.028...YOU KNOW ITS STILL NOT DONE.

That's why its useful, IF you apply the knowledge properly.

 

[Yooper]

I have to say that calculating a final gravity estimate is NOT a wasted, useless idea.

Its certainly not a hard line drawn in the sand, but if you estimate the FG (based on yeast used and how you mashed) and come to a number like 1.015...adn then after 3 weeks your stout is at 1.028...YOU KNOW ITS STILL NOT DONE.

That's why its useful, IF you apply the knowledge properly.

I absolutely agree- I hope I didn't say it wasn't important! But what I am trying to say (badly, I guess!) is that an arbitrary number is useless. A number just given by software is useless. The software doesn't "look" at ingredients and fermentability of them.

A good guestimate of FG by knowing the yeast strain, ingredients, mash temp, etc, is very useful and important! An oatmeal stout that finishes at 1.022 would be fine- a cream ale would not.

That's one reason I like this forum- if you don't have the personal experience to look at the recipe and the FG and decide if it's really done or stuck, then someone else will be able to help.

 

[Northcalais40]

There's always the old technique of waiting for at least (X) weeks, then checking the gravity. If you get the same reading (Y) days later, you're done. You may also choose to age it for (Z) (insert your preferred time metric).

 

[Brewnoob6120]

I'm taking Yooper's advice and waiting a few days and I will check it again, on another note i'm brewing a batch of AG Scottish Ale and i'm going about it a little different. I'm going to get a pre-boil gravity and a post boil also, and I do understand now that alot of the numbers that Beersmith spits out are just general guidlines to follow, and if I "smell what your stepping in" so to speak, that these numbers are helpful in determining the final product. Thanks all.