SG problems

I brewed a batch of Irish Stout. The problem is that my SG should have been between 1.040 and 1.056. When I racked it after two weeks into a secondary fermenter I took a SG reading and I got an SG of 1.020. I bottled it two days ago and the reading was still 1.020.

Any help with this? Could I have repitched the yeast?
How is this going to affect the beer?

recipe? yeast used? A lot of yeast stalls out at 1.02. you say the SG should have been btw 1.04-1.056...What was it? It the yeast stalled at 1.02 and was not stalled due to low temp you should be fine. If it stalled because temp dropped below the yeast range and you added sugar and raised temp you might have made bottle bombs

Chances are the yeast stalled and been will be fine.

Hard to tell without more details...

Just to be clear - 1.040-1.056 is supposed to be the gravity you start with. After 2 weeks it should be lower than that, so 1.020 is ok.

If the question is "shouldn't it be lower than 1.020?", often extract beers stall out around there. Was your recipe mostly extract? Also, for a stout, a FG that high will probably taste fine. I had an early Porter that stalled there and it tasted great!

The FG should have been between 1.040 and 1.056. It was all extract liquid and dry. I did add priming sugar before I bottled the beer. Hopefully I don't have any beer bombs

OK, we need some definitions here:

SG - Specific Gravity - Specific Gravity is a scientific term that means "density". Water has a density of "1.000" (g/cm^3, but this doesn't matter). Sugar raises the density of water. Alcohol is less dense than water. Therefore, your wort will start with a SG that is high, then the SG will drop as it ferments and sugar turns to alcohol.

OG - Original Gravity - this is the STARTING Gravity of the beer, in other words it's the specific gravity (SG) just before/after you pitch the yeast, before any fermentation starts. Usually this is 1.035 or above, (sometimes much above)

FG - Final Gravity - this is the ENDING Gravity of the beer. After the yeast eats all the sugar and turns it to alcohol and CO2 farts, the specific gravity (SG) is called the FG. Usually this is 1.020 or below, (sometimes far below).

So, your beer should have STARTED at around 1.040-1.056, (I'm guessing here). The OG should have been 1.040 to 1.056. It should have ended, (FG) at around 1.012-1.020.

The OG is the SG at the start, the FG is the SG at the end...make sense? OG is just easier than saying "SG at the start", and FG is just easier than saying "SG at the end", but they meant the same.

Long story short, you are probably fine.

"FG" of 1.040 to 1.056? As in "finishing gravity?" Don't think so.

If you had a starting (or "original") gravity of 1.056 and fermented down to 1.020 you would have something like 4.7% ABV which seems a bit low. Having said that from poking around a bit I see 1.020 FG for a stout is not unheard of. I would have expected it to end up somewhere south of 1.015 from the stouts/porters I have made.

The good news is your stout is probably going to be fine.

SG or you starting gravity, is the gravity after cooling the wort and before fermentation. FG, final gravity or finishing gravity is the gravity after fermentation of the wort is complete. As stated above, if your SG is a higher gavity, like 1.045 or 1.055, then your doing good. If your final gravity is a low number like 1.020 or 1.011, then the yeast has completed the fermentation process. There are a few factors thAt could have stopped the process at 1.020. In any case you abv and sweetness of the beer will change alittle but you should have a good beer in any case

bill10827 said:

The FG should have been between 1.040 and 1.056.

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are you sure???? those sound more like OG readings.

I'm a noob with a similar situation. Hope this is within the thread..
Q: Can yeast be too robust and burn itself out before finishing?
My Dunkelweizen had an OG of 1.056 and never dropped below 1.018.
The odd thing is that fermentation was "very aggressive". It was my first time with a yeast starter (Munich) and I had activity within 6 hours. Then krausen blew through the air lock (Ail Pail with only 5 gallons) at 18 hours. Then slowed to nothing by 48 hours. After 4 days I took an SG at 1.018 and it was the same at 11 days so I called the FG at 1.018 -- and bottled. Could I, should I have done more?

Ziggybrew said:

I'm a noob with a similar situation. Hope this is within the thread..
Q: Can yeast be too robust and burn itself out before finishing?
My Dunkelweizen had an OG of 1.056 and never dropped below 1.018.
The odd thing is that fermentation was "very aggressive". It was my first time with a yeast starter (Munich) and I had activity within 6 hours. Then krausen blew through the air lock (Ail Pail with only 5 gallons) at 18 hours. Then slowed to nothing by 48 hours. After 4 days I took an SG at 1.018 and it was the same at 11 days so I called the FG at 1.018 -- and bottled. Could I, should I have done more?

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No, you were good, all was well. I'm guessing it was an extract brew? Extracts are notorious for not dropping low, (I never had one go below 1.020). The problem with extracts is there's no good way to know the fermentability of them - they are a black box.

I don't think I've ever heard of yeast burning itself out. If it gets too COLD, it can go dormant, but fermentation is exothermic, which just heats up the wort, which makes them ferment faster, which heats up the wort more, etc....so you did right.

Ziggybrew said:

Q: Can yeast be too robust and burn itself out before finishing?
My Dunkelweizen had an OG of 1.056 and never dropped below 1.018.
The odd thing is that fermentation was "very aggressive". It was my first time with a yeast starter (Munich) and I had activity within 6 hours. Then krausen blew through the air lock (Ail Pail with only 5 gallons) at 18 hours. Then slowed to nothing by 48 hours. After 4 days I took an SG at 1.018 and it was the same at 11 days so I called the FG at 1.018 -- and bottled. Could I, should I have done more?

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well its probably to late to be asking this but do you have any idea what your fermentation temps where? keep in mind that the temp of the wart is higher than the room temp during the "very aggressive" phase. i would of moved the bucket to a warmer place and shook it gently to get the yeast up into suspension. yeast will slow or even stop fermentation if the temp gets to low.

i am currently brewing a cream stout. it had an aggressive fermentation then slowed and stopped. when i checked its temp it was at 59F and sure enough the FG was to high. so i bought a fermwrap, thermowell carboy cap, and a Ronco ETC. i used these to keep the beer at the target temp of 68F and sure enough fermentation picked up again.

Yes, the yeast was pitched at 75 degrees and it took about 8 hours to level-off and hold between 64 and 68 for the duration of fermentation.

Maybe for an extract kit I should run warmer?

Ziggybrew said:

Maybe for an extract kit I should run warmer?

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no the temp depends on the yeast not the extract. once the yeast are done fermenting they are done. more heat wont make them suddenly be able to ferment unfermentable sugars in your wort.

like others have said you don't know how the extract was made. lots of things can affect a worts fermentability and the resulting extract made from it. if your using extract and you have done everything you can to "unstick" a fermentation and it sill wont go down then your probably done.

Thanks. learning more with every batch.

yeast are the key...some yeast like muntons and coopers are notorious for crapping out at 1.02, others like us-05 and notty will produce a cleaner finish and usually a lower FG. Just depends on what you are looking for.