FG Issue

Lots of possibilities, a couple of which are:

1. The yeast weren't done yet. They don't care about arbitrary time-frames.
2. You didn't get the expected attenuation due to some factor (low pitch rate, not enough O2, etc.)

 

Help us with more details so we can help you. What is your recipe? I'm going to assume you're an extract brewer. Fermentability varies with extract type. Some have more simply sugars, which will ferment. While others have more complex sugars. Along those lines your specialty grains, also referred to add steeping grains, are mostly unfermentable by brewers yeast. Next, yeast makes a difference. Some do better at converting availability sugars to alky, referred to as yeast atinuation. Additionally, yeast will quit fermenting from an alcohol, threshold; although I don't think that happened here. Bottom line, need more info to see why you didn't ferment more.

 

It could, air-lock activity isn't the best indicator. As a new brewer you would be best served to let your beers go at least 2-3 weeks before thinking about sampling/transferring/bottling. Also, for most beers, there is no need to transfer to secondary unless you are going to be aging on something (wood, fruit, etc.)

 

Yes! I just brewed a beer with no more activity and took a reading and it was 1.016, target was 1.010. I took a gravity reading a few days later and it was 1.014 and it eventually finished out at 1.012. No activity for a week but it was still fermenting slow.

If you are sure it's done, by gravity samples, and the FG is higher than you want and is tasting sweeter than you want there are option such as adding more yeast to help it ferment out. As, Johnsnow said, poor attenuation is due to not pitching enough yeast, not Enough fermentables or poor O2.

My guess is you brewed a big stout and only pitched 1 dry yeast packet you came up way short on enough enough yeast cells to ferment the beer appropriately. The best way to make good beer is pitching enough healthy yeast. Yeast and fermentation is key to good beer.

 

This might be a stupid question, but is it possible that extract stouts just don't attenuate well? Any reason that might be the case? I've done 14 extract batches in the last year and a half, mostly IPAs and 4 stouts. Never had a problem with the FG of any of the IPAs, but all 4 stouts finished high. I pitched plenty of yeast, even re-pitched once or twice, and I thought I oxygenated plenty.

Here are my gravity readings from my 4 extract stouts.
OG: 1.082, FG: 1.034
OG: 1.094, FG: 1.034
OG: 1.063, FG: 1.031
OG: 1.090, FG: 1.036 (this one had a pound of lactose)

When I saw the thread title "FG issue" and didn't recognize the avatar I thought, "I bet it's gonna be an extract imperial stout".

 

Can you provide more details on what extract/specialty grains you used to brew your high gravity stouts?

Dark malt extracts will include dark specialty grains (e.g., Roasted Barley, Black Malt, etc.). Dark specialty grains include a lot of unfermentable sugars (e.g., dextrins) which will result in a high(er) final gravity.

If you brew your stouts using pale malt extract and steep the specialty grains you will have more control on what final gravity you achieve since you have control over the amounts of specialty grains used (and consequently the amount of dextrins in the wort).

Cheers!

 

IMHO: If brewing an Imperial anything...use at a minimum, 2 sachets of dried yeast
Don't brew an Imperial anything until you have kicked kits to the curb, can oxygenate, and have brewed a bunch of above ave. regular beers.

 

Glad to hear it is working out well for you. Because of the style, I would recommend you let it sit in bottles for an extended time. Look up the topic of bottle conditioning.

 

For next time:
I had this exact same issue. I ended up pitching S-33, checked my gravity constantly until I was happy with the gravity then cold crashed it. You need to be careful with high attenuation yeast as they could finish out below where you would like your beer to finish.

 

Just curious, did you rehydrate the yeast before pitching?

 

You are correct in my experience; extract batches often don't attenuate very well.

A couple of other things also going on:

1) Maltodextrin is not fermentable. A big no-no for any extract recipes unless you like drinking thick syrupy motor oil.

2) You removed ~90% of the yeast too early when you racked to secondary after 1.5 weeks. I would have given this batch at least 2 weeks if not 3 or 4 weeks in the primary. Patience is a virtue. Give the yeast plenty of time to do their job.

In future, for big extract beers, swap out a pound of base extract for a pound of cane sugar. Results should be much improved since cane sugar is 100% fermentable while extract is often <70% fermentable, depending on the manufacturer and choice of yeast strain, etc.

 

Dm and tebuken both brought up questions I wanted to ask but didn't bother because it was too late anyways.

but DB answered a question I had about WHY people suggest to swap out cane sugar for extract. At what threshold do you make the swap? When your expected OG is 1.08x? and a pound of sugar replacing a pound of extract sounds like overkill - too much sugar.

 

For some reference, I recently brewed a 100% extract beer that was 1# wheat DME, 6# light DME and 1# turbinado sugar in about 6 gallons of liquid (tons of hop absorption). It finished right at 1.010, which is probably a point or two per gallon lower than where it would have finished without the sugar based on my experience with WLP013. Dropping a point or two in a beer finishing well into the 20's probably wouldn't make much of a difference aside from ABV.