Stuck vs. Complete Fermentation

[inturnldemize]

I understand the difference between the 2 but how do I know when one is taking place as opposed to the other? Is there a thin line between the 2? Is there a calculation to see if fermentation has completed?

 

[RobbyBeer]

You could give the fermenter a quick swirl to bring the yeast back into suspension.. If you still do not notice any air lock activity after a few hours, it's most likely finished and not stuck. The only sure way to tell is to use your hydrometer everyday. If you're taking the same reading for 3 days in a row, your fermentation is complete.
Cheers!

 

[Golddiggie]

There are a few ways... If you're all grain brewing, and use software that takes mash temps into account (like BeerSmith 2.x) and you account for the attenuation range of the yeast, you'll be able to tell if the batch is stuck or finished.

A stuck fermentation is usually far above projected FG.

For example, if you mashed at 150F with mostly base malt (95%+) with an OG of 1.057 and estimated FG of 1.011 with a yeast that can get to that much attenuation, but only hit 1.03x then it's stuck. Or you mashed far higher than you thought.

I would download a free trial of BeerSmith (if you don't already have it), enter the recipe for your brew into it and see what it gives for an estimated FG.

IMO, using your hydrometer 'everyday' is a colossally BAD idea. Give your brew at least a week or three before you open it up to pull a sample. Every time you open up the cover or pull the stopper you run the risk of contamination/infection. IME, it's better to WAIT until it appears finished BEFORE you start testing. You can tell if it's fermenting, or not, by temperature of the fermenting beer. IF it peaks, and then drops down to ambient, chances are fermentation is finished. NOT to say that it's ready for bottles/next step, but the yeast is done with the majority of it's work. Give it some more time and then test. Also, I would go 2-4 days between hydrometer samples/readings. IME/IMO, there's no valid reason (other than your own neurosis) for pulling a sample every single day.

 

[inturnldemize]

But if fermentation was stuck, the hydrometer would also read the same for 3 days in a row.

 

[RobbyBeer]

But if fermentation was stuck, the hydrometer would also read the same for 3 days in a row.

Right, but if you know what your projected FG is and your close, it's most likely not stuck.
Give it a swirl and wait another day. Stuck fermentation almost never happens. It's more likely just completed its cycle.
Give us the rundown of your brew, grain bill, yeast, OG.. Ect.. We may be able to help more.

 

[RobbyBeer]

There are a few ways... If you're all grain brewing, and use software that takes mash temps into account (like BeerSmith 2.x) and you account for the attenuation range of the yeast, you'll be able to tell if the batch is stuck or finished.

A stuck fermentation is usually far above projected FG.

For example, if you mashed at 150F with mostly base malt (95%+) with an OG of 1.057 and estimated FG of 1.011 with a yeast that can get to that much attenuation, but only hit 1.03x then it's stuck. Or you mashed far higher than you thought.

I would download a free trial of BeerSmith (if you don't already have it), enter the recipe for your brew into it and see what it gives for an estimated FG.

IMO, using your hydrometer 'everyday' is a colossally BAD idea. Give your brew at least a week or three before you open it up to pull a sample. Every time you open up the cover or pull the stopper you run the risk of contamination/infection. IME, it's better to WAIT until it appears finished BEFORE you start testing. You can tell if it's fermenting, or not, by temperature of the fermenting beer. IF it peaks, and then drops down to ambient, chances are fermentation is finished. NOT to say that it's ready for bottles/next step, but the yeast is done with the majority of it's work. Give it some more time and then test. Also, I would go 2-4 days between hydrometer samples/readings. IME/IMO, there's no valid reason (other than your own neurosis) for pulling a sample every single day.

True, there is a risk of contamination, if you are a brewer that stores your gear in the toilet..
I don't know, just never had a sanitation issue, keep your things and work space clean.
Also true that everyday may be a bit of overkill.. Every 2 or 3 days is better.

 

[Golddiggie]

Doesn't matter how you sanitize and such, if you're opening up your vessel EVERY DAY then you will get an infection/contamination eventually. Besides, it's completely unnecessary. If you're that nervous over what your beer is doing, then you have deeper issues.

For reference, I let my batches go about 3-4 weeks (for my 'normal OG' brews) from boil to keg. I use starters for my yeast (on a stirplate) which I cold crash and decant so that I pitch more yeast than spent starter wort. I also give the brews nutrient during the boil (at the same time as the Irish Moss) to give them a leg up. I also use a pure O2 system to oxygenate the wort to a better level. I typically have full active fermentation in under 12 hours this way. I also get within the attenuation range for my yeasts (if not a bit more). I don't check the gravity on them until after they're kegged. I KNOW they're done fermenting since the temperature inside the vessel is at ambient for at least a week (or two to three) before they go to keg. I check the final gravity sample (I use a refractometer now, so I only need a tiny sample) later. Mostly to see what the ABV% is for the batch. I do make sure to have a taste of the sample, or some of what gets left in the hose from the transfer.

TIME in primary can resolve all but a few/handful of issues with brews. Contamination, infection, and oxidation are among those that cannot be fixed. Why open your batch up to all three by checking it every day?? Seems rather foolish to me.

 

[RobbyBeer]

Doesn't matter how you sanitize and such, if you're opening up your vessel EVERY DAY then you will get an infection/contamination eventually. Besides, it's completely unnecessary. If you're that nervous over what your beer is doing, then you have deeper issues.

For reference, I let my batches go about 3-4 weeks (for my 'normal OG' brews) from boil to keg. I use starters for my yeast (on a stirplate) which I cold crash and decant so that I pitch more yeast than spent starter wort. I also give the brews nutrient during the boil (at the same time as the Irish Moss) to give them a leg up. I also use a pure O2 system to oxygenate the wort to a better level. I typically have full active fermentation in under 12 hours this way. I also get within the attenuation range for my yeasts (if not a bit more). I don't check the gravity on them until after they're kegged. I KNOW they're done fermenting since the temperature inside the vessel is at ambient for at least a week (or two to three) before they go to keg. I check the final gravity sample (I use a refractometer now, so I only need a tiny sample) later. Mostly to see what the ABV% is for the batch. I do make sure to have a taste of the sample, or some of what gets left in the hose from the transfer.

TIME in primary can resolve all but a few/handful of issues with brews. Contamination, infection, and oxidation are among those that cannot be fixed. Why open your batch up to all three by checking it every day?? Seems rather foolish to me.

Yes, I don't go opening fermenters up on a whim for no reason..
I wait 3 weeks minimum on all batches.. And if I am next to certain that fermentation is complete then yes, I will check every few days to make sure it is in fact done.
Contamination has never been a concern or issue. It's "nonsense" to think it is, unless your not clean when you are doing tests or tasting.
Contamination happens when someone is not paying attention to what they are doing. Oxidation is a concern, and as far as I've seen, taking a sample from a sealed container from a spout, introduces no oxygen into the solution.