SG slightly different to FG, this okay?

[IEpicDestiny]

Hi, so I checked my SG and it was at 1.009, checked again in 48 hours time and it was 1.008. Does the slight different really matter? Am I able to bottle now? Says it needs to be stable for 2 days but I don't know if that slight difference matters.

Also my OG was 1.035 which means the abv when calculated and adding the extra 0.5% when bottled for secondary fermentation would only make it out to be 4% when it should be 4.5%. I did what the instructions say so I do not understand why the abv was lower than it says it should be.

Thanks

 

[Miraculix]

No, wait till it is stable.

 

[dmtaylor]

Do not rush it. Wait three or four more days to ensure it stays at 1.008.

 

[micraftbeer]

You will hear the general rule of thumb is stable from three readings over three days. That's because at the end, it can do a very slow drop that you might miss otherwise. 0.001 could easily be measuring accuracy error, but it could also be a slow downward trend indicating things aren't finished yet. Better to err on the side of caution and assume it's still working.

 

[IEpicDestiny]

Thank you everyone. I hear to skip the middle day of the 3 day gravity check. and I also hear to do it 2 days apart too. Which is correct?
Most people say to do it once and then check again on the third day, but what if the middle day changed?

 

[Miraculix]

Thank you everyone. I hear to skip the middle day of the 3 day gravity check. and I also hear to do it 2 days apart too. Which is correct?
Most people say to do it once and then check again on the third day, but what if the middle day changed?

Then you would also see it on the third day.

 

[IEpicDestiny]

Oh I see, is there anything wrong with doing it 2 days apart instead?

 

[Miraculix]

Oh I see, is there anything wrong with doing it 2 days apart instead?

Yes, it's too close.

 

[micraftbeer]

I know it's annoying when you ask a question and someone tells you to buy more gear. I'll resist that, and instead show you some plots of fermentations tracked from my Tilt floating in the beer. The Tilt has it's disclaimers of why the reading might not be the exact SG (fermentation vigor, natural carbonation bubbles, active krausen, dry hops, krausen/dry hop sludge stuck to it, etc.). But one thing it is great at is telling you when your yeast are finished converting sugars to alcohol.

Even if you don't go run out and buy a Tilt, just looking at the plots below, you can see the trends at end of fermentation for a random selection of fermentations I've had. These are readings every 15 minutes, which is obviously much more frequent than you would do without an electronic device automatically doing it for you. But envision the different rules of thumb referenced above of 1 sample/day for 3 days, 1 sample every other day, etc.

 

[Miraculix]

I know it's annoying when you ask a question and someone tells you to buy more gear. I'll resist that, and instead show you some plots of fermentations tracked from my Tilt floating in the beer. The Tilt has it's disclaimers of why the reading might not be the exact SG (fermentation vigor, natural carbonation bubbles, active krausen, dry hops, krausen/dry hop sludge stuck to it, etc.). But one thing it is great at is telling you when your yeast are finished converting sugars to alcohol.

Even if you don't go run out and buy a Tilt, just looking at the plots below, you can see the trends at end of fermentation for a random selection of fermentations I've had. These are readings every 15 minutes, which is obviously much more frequent than you would do without an electronic device automatically doing it for you. But envision the different rules of thumb referenced above of 1 sample/day for 3 days, 1 sample every other day, etc.

View attachment 746952

View attachment 746953

View attachment 746954

Damn asymptotic Saison always gave me gushers after a few weeks.

 

[BrewnWKopperKat]

random selection of fermentations I've had

Same strain of yeast or different strains?

 

[micraftbeer]

Same strain of yeast or different strains?

These are all different. I just grabbed 3 recent ones to show that the tail end of fermentation can have different shapes to the gravity readings, and if you don't look at it over a decent amount of time, it's easy to misjudge with single reading data points.

I could go look through the "archives" to see what I've got for same yeast. But I brew a lot of different stuff all the time. And even though I've narrowed to a few yeast strains, I frequently will have different grists, different mash schedules, different temperature/pressure.

 

[TestTickle]

Hi, so I checked my SG and it was at 1.009, checked again in 48 hours time and it was 1.008. Does the slight different really matter? Am I able to bottle now? Says it needs to be stable for 2 days but I don't know if that slight difference matters.

Also my OG was 1.035 which means the abv when calculated and adding the extra 0.5% when bottled for secondary fermentation would only make it out to be 4% when it should be 4.5%. I did what the instructions say so I do not understand why the abv was lower than it says it should be.

Thanks

Just to echo what everyone else said, do not rush it. Even when FG is reached, it can often be beneficial to give the yeast a few days to clean things up.

Also, +1 to the Tilt. They really do provide a nice window into the world of fermentation, and are almost equally as valuable for temperature control.

 

[IEpicDestiny]

Thanks for all the tips! I checked the gravity today and it is now 1.007..
When you read instructions or ask people they usually say to measure it and then measure it again 48 to 72 hours later, missing out the middle date. Are people assuming it has stabilised on that middle day? Or do we ignore that and only count it if the measurement is the same in 48 hours?
Because mine has been 24th: 1.009 26th 1.008 27th 1.007. So on the 28th if it is 1.008 it is ready to bottle?

What should I do?

 

[balrog]

You should walk away for a week.

Seriously.

Nothing good comes from doing things too quickly, and nothing bad happens if you wait a week.

 

[Miraculix]

Thanks for all the tips! I checked the gravity today and it is now 1.007..
When you read instructions or ask people they usually say to measure it and then measure it again 48 to 72 hours later, missing out the middle date. Are people assuming it has stabilised on that middle day? Or do we ignore that and only count it if the measurement is the same in 48 hours?
Because mine has been 24th: 1.009 26th 1.008 27th 1.007. So on the 28th if it is 1.008 it is ready to bottle?

What should I do?

If it is higher on the last day then the day before, then you misread the result at least once.

 

[IEpicDestiny]

If it is higher on the last day then the day before, then you misread the result at least once.

That is strange though, I do make sure my readings are accurate, making sure it doesnt touch the sides, and re doing it multiple times to make sure.

 

[Miraculix]

Gravity does not increase unless the temperature of the liquid changes. The gravity only stays the same or gets lower.

 

[micraftbeer]

That is strange though, I do make sure my readings are accurate, making sure it doesnt touch the sides, and re doing it multiple times to make sure.

Have to remember that every measuring system has some repeatability error. A variation of +/- 0.001 SG is not shocking at all to me.

Thanks for all the tips! I checked the gravity today and it is now 1.007..
When you read instructions or ask people they usually say to measure it and then measure it again 48 to 72 hours later, missing out the middle date. Are people assuming it has stabilised on that middle day? Or do we ignore that and only count it if the measurement is the same in 48 hours?
Because mine has been 24th: 1.009 26th 1.008 27th 1.007. So on the 28th if it is 1.008 it is ready to bottle?

What should I do?

I have frequently got caught up in this. I think it's important to note that sometimes we get fixated on understanding what exactly is happening and that can obscure from a practical standpoint what should be done. In the case of gravity readings at the end of fermentation, you might be at the end of fermentation on say the 26th from your numbers above. However, defining that true end of fermentation might help your understanding of what's going on- but that doesn't mean pack it up and stick it in a keg right away or put it in bottles. And that's where the advice of "walk away for a couple days" comes from. Maybe/probably the yeast has finished converting sugars to alcohol. But there is "clean up" that is often cited that the yeast do after fermentation is complete. And that clean up doesn't come with a corresponding drop in gravity. So just keep in mind that the official declaration of "end of fermentation" is not the same thing as "time to bottle/keg".

 

[TestTickle]

You should walk away for a week.

Seriously.

Nothing good comes from doing things too quickly, and nothing bad happens if you wait a week.

This right here. Out of curiosity @IEpicDestiny, how many days has it been fermenting?

 

[balrog]

That is strange though, I do make sure my readings are accurate, making sure it doesnt touch the sides, and re doing it multiple times to make sure.

Fermentation is the act of creating alcohol and CO2. Some of that CO2 dissolves in the <whatever temp> beer. That's why you have to account for it when calculating priming sugar amounts. Now that dissolved CO2 stays dissolved unless you change the temp and/or pressure of the system. A bomb cyclone comes through, drops your area barometric pressure, and lo and behold, CO2 will come out of solution and make airlocks go again. THe other thing that will knock CO2 out of solution is agitation and nucleation points.

All this simply to say, you MAY have had some bubbles on the hydrometer to float it higher to make it appear that a higher SG reading happened.

 

[IEpicDestiny]

This right here. Out of curiosity @IEpicDestiny, how many days has it been fermenting?

13 days now.
I would really love to know exactly what I should do. I know I might get hated on this but there is this professional brewer on youtube and he says that you really do not need to ferment for 3 weeks despite everyone telling you you should. Apparently because that is an old saying and it is found to not be necessary anymore. I have made good beer before fermenting for only 7 days too. I just want to be extra careful this time because my last batch messed up somehow

 

[balrog]

Not at all. But "exactly what to do now" is kinda tough in this homebrewing universe, and when multiplied by the interwebz, you will find that asking a seemingly simple question will likely get you millions of opinionated replies.

English strains of yeast seem to take me longer to finish.
Darker/stronger beers take longer to finish.

13 days is actually pretty good. I would wait a couple days and measure again, but without knowing more about the recipe and yeast and process and even more things, it is really hard to say what exactly to do now.

 

[TestTickle]

13 days now.
I would really love to know exactly what I should do. I know I might get hated on this but there is this professional brewer on youtube and he says that you really do not need to ferment for 3 weeks despite everyone telling you you should. Apparently because that is an old saying and it is found to not be necessary anymore. I have made good beer before fermenting for only 7 days too. I just want to be extra careful this time because my last batch messed up somehow

Three weeks is unnecessary in most cases, but with that said, it's really dependent on a variety of factors like yeast health, pitching rate, fermentation temperature and yeast strain. The bottom line is that the yeast will be done when it's done. I have some beers that are done in a week, most are around 10 days, but some take a couple of weeks.

We aren't saying that the beer isn't done, it's very possible that it is. But if there is any question at all, the safe bet is to be patient and wait. Don't check the gravity every day. Check it now and wait two or three days. If it's the same, then bottle it. Or, as mentioned earlier, walk away for a week and call it good.

Patience can be the difference between a good beer and a great beer.

 

[dmtaylor]

there is this professional brewer on youtube and he says that you really do not need to ferment for 3 weeks despite everyone telling you you should. Apparently because that is an old saying and it is found to not be necessary anymore. I have made good beer before fermenting for only 7 days too. I just want to be extra careful this time because my last batch messed up somehow

Keep in mind, the professionals are typically kegging it, whereas some homebrewers don't keg but are bottling it. If you keg it, you can likely get away with kegging it early. But, if you are bottling it, and you move it into bottles too soon... you've got potential gushers or bombs on your hands.

Regardless, there is NO SET NUMBER OF DAYS FOR ANY FERMENTATION. Yeast is a living organism, and it is affected by hundreds of variables. Yeast will work on its own schedule, not always on the schedule that humans desire. Don't ever forget it.

Many Belgian yeasts are extremely fussy and can take 3-5 weeks to complete fermentation. German ale yeasts sometimes take 5-7 weeks. On the other hand, some British yeasts are consistently finished in exactly 36-40 hours every single time.

There is no consistent rule of thumb for most yeasts. Let the specific gravity guide you. The best advice I can give on this, which I've said in the past and I'll say it again:

Wait until you think fermentation is definitely complete. Then check gravity. Then wait at least 3-4 more days. Then check again. If you were right and the gravity did not change by even one single point, then it's done and safe to package. If not, then fermentation is NOT complete, and you need to continue the cycle every 3-4 days until it's stable.

Unless you're kegging. This guidance is true but is more important when bottling. If you're kegging, you can get away with sins to some extent, at the expense perhaps of a few pints of hazy yeasty beer for a few days, and potential for "green" flavors including extra sulfur or diacetyl.

 

[jrgtr42]

13 days now.
I would really love to know exactly what I should do. I know I might get hated on this but there is this professional brewer on youtube and he says that you really do not need to ferment for 3 weeks despite everyone telling you you should. Apparently because that is an old saying and it is found to not be necessary anymore. I have made good beer before fermenting for only 7 days too. I just want to be extra careful this time because my last batch messed up somehow

There's no harm in leaving it be.
In fact, in my homebrewing experience, I get a better result when I leave it the 3 weeks versus 2.
I have a fresh hop ale that's been slowly chugging away for 5 weeks now. |IT's not infected or anything, it just hasn't gotten down to final gravity yet.
There are things you can do, and that professionals do, to hurry things along - some of them will go from grain to glass in under a week. IT has to do with yeast pitchnig rates, temperature control, aeration, and a gaggle of other things.
But as a homebrewer, there's little incentive to rushing a beer out, other than clearing a vessel to brew again.
Honestly, patience is the hardest thing for any brewer to learn, especially new-ish homebrewers. Instructiions will say to rack after a week or two - the yeast don't read those directions. They'll finish up when they're good and ready to.
I would recommend leaving it along for a few more days. There's nothing to be gained by constantly checking gravity, and each time you open the fermenter you risk infection and oxidation.

 

[IEpicDestiny]

Fermentation is the act of creating alcohol and CO2. Some of that CO2 dissolves in the <whatever temp> beer. That's why you have to account for it when calculating priming sugar amounts. Now that dissolved CO2 stays dissolved unless you change the temp and/or pressure of the system. A bomb cyclone comes through, drops your area barometric pressure, and lo and behold, CO2 will come out of solution and make airlocks go again. THe other thing that will knock CO2 out of solution is agitation and nucleation points.

All this simply to say, you MAY have had some bubbles on the hydrometer to float it higher to make it appear that a higher SG reading happened.

So is it impossible to tell the reading of a hydrometer then? I would degass the sample too just to make sure

 

[IEpicDestiny]

Not at all. But "exactly what to do now" is kinda tough in this homebrewing universe, and when multiplied by the interwebz, you will find that asking a seemingly simple question will likely get you millions of opinionated replies.

English strains of yeast seem to take me longer to finish.
Darker/stronger beers take longer to finish.

13 days is actually pretty good. I would wait a couple days and measure again, but without knowing more about the recipe and yeast and process and even more things, it is really hard to say what exactly to do now.

True that, pretty much any simple question I have is impossible to find the answer for on the internet. Everything always needs to be more complicated than it is I think..

I am only doing a Simply Ritchies Lager kit lol. Sure if I was doing a high abv beer then 3 weeks would make sense, but this is only 4%

 

[IEpicDestiny]

Three weeks is unnecessary in most cases, but with that said, it's really dependent on a variety of factors like yeast health, pitching rate, fermentation temperature and yeast strain. The bottom line is that the yeast will be done when it's done. I have some beers that are done in a week, most are around 10 days, but some take a couple of weeks.

We aren't saying that the beer isn't done, it's very possible that it is. But if there is any question at all, the safe bet is to be patient and wait. Don't check the gravity every day. Check it now and wait two or three days. If it's the same, then bottle it. Or, as mentioned earlier, walk away for a week and call it good.

Patience can be the difference between a good beer and a great beer.

Is it not possible to tell when it is truly done then? How would you know its done in 7 days? I think I'm starting to get it now. So if I left it for another week, would I even need to bother with the readings? It would definitely be done? The readings definitely don't seem to be completely accurate, temperature could also be a cause for it to change slightly

 

[micraftbeer]

Is it not possible to tell when it is truly done then? How would you know its done in 7 days? I think I'm starting to get it now. So if I left it for another week, would I even need to bother with the readings? It would definitely be done? The readings definitely don't seem to be completely accurate, temperature could also be a cause for it to change slightly

If you're truly vested in wanting to know when it's done, you need something like a Tilt, taking gravity readings every 15 minutes. If you refer above to 3 different plots from fermentations I've had recently, you can see they all have slightly different slopes. So when you're grabbing a single data point once/day, you can easily envision how "the same" readings might actually be a slowly dropping line.

If you want to know exactly when it's done, get a Tilt and take readings every 15 minutes. If you're going to take readings once per day, you have to accept the limitations of your data sampling rate, and you might have to err on the side of letting the beer sit longer in the fermentor just to make sure.