How do YOU know when fermentatio is done?

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When do you determine fermentation is done

  • If I hit my target FG on my first reading, it's done.

  • If I hit my target FG on my first reading, I still wait and take another, 2 days later.

  • Other- Please explain.


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JeffoC6

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Here's a question for everyone. There is no right or wrong answer, but I'm curious as to what the consensus is regarding this outlined procedure:

Target FG is 1.015
You take your first FG reading 19 days into a 21 day primary fermentation.
At day 19, your FG is 1.015.

Do you, or do you not take another FG reading on day 21?

If "other," what DO you do?
 

BrewinHooligan

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I don't really pay much attention to what my recipe and software tell me the FG should be. Yeast are animals and do what they want. I generally take 3 readings before packaging to make sure gravity is stable and I taste each sample to get a feel for how it's coming along and if I think it may need some time to age.
 

ErnDollas

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The FG is more of a guide to know the ballpark of where your gravity reading should be after fermentation, assuming full attenuation dependant on the yeast strain. When you take your reading and write it down and take another in a couple days if they are the same than the yeast is more than likely done. There are many reasons you may finish above what you have calculated as your final gravity but have a beer that is no longer fermenting. On the other side if you take a reading and it is at your FG it doesn't mean that fermentation is complete the yeast may still be working. If you move straight to bottling without making sure your gravity readings have stabilized you could end up with bottle bombs. I always rack to a secondary though. I let it sit in primary for typically 7 days, my gravity readings at that point are usually near the FG for the beer. Rack to my secondary and let it sit for about 10 days that is when I usually take another gravity reading and let it sit for another 2 or 3 days and take another. I have never had one that wasn't finished.
 
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A recipe doesn't tell you what the FG will be, just an estimated target FG. You need to make sure your beer is finished, i.e. you have a stable FG, before you want to move in off the yeast. Therefore, just taking one gravity reading would be pointless really. What if your particular batch is to ferment down -2 points of your target and your first FG reading is at the target?
 

dgez

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I voted other. I generally let ales stay in primary for a month and lagers 6 weeks. I figure if it hasnt hit FG by then it never will. I take 1 reading at that time before I transfer to 2ndary for crash cooling / lagering. One and done.
 

JohnnySardonic

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I know my beer is done fermenting when it talks to me in my dreams and tells me it's ready to be bottled. It's like a sixth... no, seventh sense.

But in all honesty I agree with the previous posts. Two gravity readings with a day in between. If SG is stable, fermentation is done. Then I leave it for 5-7 days, depending on when I have enough time to bottle. That gives me some piece of mind in case my home brew'd vision caused me to read the hydrometer wrong by a point or two.
 

Stauffbier

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I take a reading after about 3 weeks. I then check to see how much my attenuation is at that point. If it's at or above the high end of my yeasts attenuation rating I bottle. If it's at or below the low range then I leave it a week and take another reading...
 

dale1038

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Goodness, you guys are doing too much work for me. Although, it really depends on my pipeline. If its low, 10 days and keg that sucker up. If the pipeline is good, let it ride for a month and keg. I've never in my life taken more than 2 gravity readings. I do sit my carboys right next to my bed and whisper sweet nothings into my yeasts ears all night, so that may be you alls problem.
 

nealizm

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Wave your hand in front of the fermenter and say "these aren't the sugars you are looking for" and it is complete,bottle or keg as needed.
 

HopSong

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I take a gravity reading at 10 days.. another at 15 days and another at 20. If stable, I consider it finished, but may leave it in the FB beyond 20 before bottling/kegging.
 

tre9er

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If you're anxious, take gravity readings for a few days and look for stability. If you're not anxious, let it wait a month. Sure to be done by then
 

Pilgarlic

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I wait for the beer to clear in primary. FG is a prediction, not a goal.
 

shelly_belly

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I wait until the yeast give up and fall to the bottom. Then, when I rack, I take a gravity reading so that I can determine the ABV.
 
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NordeastBrewer77 said:
You need to make sure your beer is finished, i.e. you have a stable FG, before you want to move in off the yeast. Therefore, just taking one gravity reading would be pointless.
At least 3 gravity readings starting when you expect fermentation to be done and yeast has had time to clean up a bit (no earlier than 2 weeks). When FG is stable for 3 straight days and your beer has cleared, rack off the yeast to secondary or get ready to bottle. Either way, stable FG and time to clear and clean up is what I go for.
 
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At least 3 gravity readings starting when you expect fermentation to be done and yeast has had time to clean up a bit (no earlier than 2 weeks). When FG is stable for 3 straight days and your beer has cleared, rack off the yeast to secondary or get ready to bottle. Either way, stable FG and time to clear and clean up is what I go for.
Exactly! Unless I'm trying to turn a brew around quickly, I use the 'beginning to fall bright' method to tell me when to take the first FG reading.
 

hepcat

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For beers, I'd start checking it after 5-6 days fermentation. Then check it again 2-3 days later. If it hasn't moved/dropped any further, it's done. Simple.
 

tre9er

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NordeastBrewer77 said:
Exactly! Unless I'm trying to turn a brew around quickly, I use the 'beginning to fall bright' method to tell me when to take the first FG reading.
Buckets. Fail. Have to open and check gravity.
 
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Buckets. Fail. Have to open and check gravity.
Do you have the lids with just the grommet? Cuz yeah, then you have to do that. I use glass a lot for primary (ducking the flames) and the lids I have for my buckets have a hole for a bung, so I just pop that open and take a look. It's also just safe to assume after 2 weeks, the beer's clearing and you can start your FG readings then.
 

tre9er

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I want a well that I can take samples from without opening lid. Also want a bung four a dial thermometer. #hightechbuckets
 

MalFet

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Other. I do pressurized ferments in cornies, and I've got a mass flow controller hooked up to my gas post. I know my fermentation is done when the pressure holds steady and my beer stops releasing out measurable quantities of CO2. Plus, by totalizing the gas released, I've been getting an accurate estimation of my gravity without needing to take a sample.

Too complicated, yes, but that's why here here, right? :D
 

BrewKnurd

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MalFet said:
Other. I do pressurized ferments in cornies, and I've got a mass flow controller hooked up to my gas post. I know my fermentation is done when the pressure holds steady and my beer stops releasing out measurable quantities of CO2. Plus, by totalizing the gas released, I've been getting an accurate estimation of my gravity without needing to take a sample.

Too complicated, yes, but that's why here here, right? :D
Why am i not the slightest bit surprised to learn this, malfet? :D
 

Kate00

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I wait until it just looks like its starting to wrap up. The airlock will slow down, the krausen will fall, and the beer will clear up. I'll take a hydrometer reading and drink the samples a couple days in a row. if it has the same reading and tastes good a couple days in a row i bottle. I've noticed that the green taste of a beer will go away even with the same hydrometer readings, and it pretty much tastes the same after it starts tasting good, if that makes sense. I tried the month primary with an amber ale a few months ago, and it started clearing after a week, tasted better on week two than on week one (some funky bitter tastes go away when the yeast cleans up after itself), and tasted pretty much the same for weeks 2, 3, and 4. The beer turned out great, but I could have bottled after week two, which i have with several very good batches.

So, i say use a couple hydrometer readings for consistent gravity, and if it tastes like you want also, bottle it up.
 

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