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brybry

Using a hydrometer to check fermentation

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I'm 12 days into fermenting my second batch, I'm not trying to rush it I'm still planning on going to about 19 days before cold crashing, then bottling. But wanted to learn how to use a hydrometer to check to see if fermentation is complete. I remember seeing the procedure in the forums but can't seem to find it now that I'm looking for it. From what I remember it is.

 

- at around 2 weeks take a sample and record the SP

- wait some period was it 24 hours or 48 hours and read the SP of the same sample again

- Compare the 2 SP readings if there is no change the fermentation is done

 

Can someone confirm did I remember this correctly?

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Link in my sig to that post.

 

Assuming you mean "SG", specific gravity, you wait 48 hours.  

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Thanks, Rickbeer. For this testing do you use the same sample, just let it set next to the LBK for 48 hours or pull a second sample 48hours later?

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Thanks, Rickbeer. For this testing do you use the same sample, just let it set next to the LBK for 48 hours or pull a second sample 48hours later?

Rick must be outside feeding his livestock right now. That worm farm takes a lot of attention. So I'll try to help you. Hope I get it right. Better to take a new sample for 2nd reading. Not saying the 1st sample won't work. Just that a sample from the full vovolume is the better bet.

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Correct.  So if you plan on doing this when you know the beer isn't ready, then AGAIN at 19 days, that's 4 samples you're not putting into bottles.  About one bottle in total.

 

I was feeding the MSU coeds, aka cows.    :lol:

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Better to take a new sample for 2nd reading. Not saying the 1st sample won't work. Just that a sample from the full vovolume is the better bet.

 

Correct.  So if you plan on doing this when you know the beer isn't ready, then AGAIN at 19 days, that's 4 samples you're not putting into bottles.  About one bottle in total.

 

I was feeding the MSU coeds, aka cows.    :lol:

 

Thanks guys. Not planning on starting this early with every batch, but wanted to start "early" ,knowing it'll keep some beer out of the bottles, so I can see the change. I'm really trying to learn from these first couple of batches.

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If I can make a personal suggestion here?  Forget the hydrometer.  I have one and I use to use it religously.  It now collects dust somewhere in my cellar.  Wasting beer is all you're doing.

 

We have to remember we're just home brewers here.  We don't need all the chemistry and mathmatics(sp) the big boys use.  Stick with the KISS approach and RDWAHAHB.  Let that beer sit in the fermenter for three weeks. It's done.  Bottle it.  Let it condition in the bottles for four weeks.  They're ready to chill.  Chill them for three or four days.  They're ready to drink.  Do so.  Don't worry about what the ABV is.  It is what it is.

 

Worry now about getting your procedures down.  After you get a few batches under your belt where everything goes as planned when planned then you can move on to the next level and work at getting those procedures down.  Then move on to the next level after that and on and on.

 

As long as you stick to the 3 week fermentation and four week conditioning and all of your procedures are followed correctly you'll make excellent beer.

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So I took a sample. Observations is the wort is still very cloudy, and a good amount of tiny bubbles in the sample cylinder.

 

3/11 OG 1.041

3/22 SG 1.015

 

This would give me a current ABV of 3.4%. So based on the target of 4.7% ABV. And the FG from my first batch of Aztec which was 1.012, is it safe to expect that since my Aztec hit a FG of 1.012 that the Aztec Deluxe with an LME added should also hit a FG of 1.012?

 

I'd say as expected at 11 days the beer ins't done. Correct?

 

Also after the reading I tasted the sample and was surprised on the amount of carbonation, I guess the bubbles in the sample should have tipped me off that there would be carbonation.

 

Any thing else I can learn from this?

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So I took a sample. Observations is the wort is still very cloudy, and a good amount of tiny bubbles in the sample cylinder.

 

3/11 OG 1.041

3/22 SG 1.015

 

This would give me a current ABV of 3.4%. So based on the target of 4.7% ABV. And the FG from my first batch of Aztec which was 1.012, is it safe to expect that since my Aztec hit a FG of 1.012 that the Aztec Deluxe with an LME added should also hit a FG of 1.012?

 

I'd say as expected at 11 days the beer ins't done. Correct?

 

Also after the reading I tasted the sample and was surprised on the amount of carbonation, I guess the bubbles in the sample should have tipped me off that there would be carbonation.

 

Any thing else I can learn from this?

Can't compare the FG of this batch to the FG of the previous batch without knowing the OG of the previous batch. Even then, one batch may have more or less non-fermentables than the other.

It does indeed sound like you should expect this FG to drop down another 4 or 5 points.

It's good that you're taking the time to get to know the habits of the brew. Keep it up. As Chuck said, the day will come when you know what's going on with your beer almost on instinct alone, plus faith in the process you've grown to understand so well.

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Use your hydrometer to get a good idea of what is happening during fermentation, however, I would still give the brew a full three weeks. Don't rush, the yeast are still active and are consuming more that malt sugar. Just a suggestion. 

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I like taking the hydro readings.  Knowing where you are in the cycle of fermentation is very educational.  I also like to do that final Abv calculation and to taste the sample each time leading up to it.  Yinz with the dusty hydros know what to expect but for the rest of us I think this is a cheap and important part of the process.

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If I can make a personal suggestion here?  Forget the hydrometer.  I have one and I use to use it religously.  It now collects dust somewhere in my cellar.  Wasting beer is all you're doing.

 

We have to remember we're just home brewers here.  We don't need all the chemistry and mathmatics(sp) the big boys use.  Stick with the KISS approach and RDWAHAHB.  Let that beer sit in the fermenter for three weeks. It's done.  Bottle it.  Let it condition in the bottles for four weeks.  They're ready to chill.  Chill them for three or four days.  They're ready to drink.  Do so.  Don't worry about what the ABV is.  It is what it is.

 

Worry now about getting your procedures down.  After you get a few batches under your belt where everything goes as planned when planned then you can move on to the next level and work at getting those procedures down.  Then move on to the next level after that and on and on.

 

As long as you stick to the 3 week fermentation and four week conditioning and all of your procedures are followed correctly you'll make excellent beer.

 

What Chuck N says makes good sense except that in practice it is not self evident that three weeks always and invariably results in a finished fermentation. If it does not and if the beer is still fermenting in the bottle then adding the appropriate amount of sugar to prime may in fact result in over carbonating the beer. It doesn't matter whether you are a home brewer or a professonial brewer, allowing beer to ferment in the bottle measn that you have no real control over the level of carbonation...

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If I can make a personal suggestion here?  Forget the hydrometer.  I have one and I use to use it religously.  It now collects dust somewhere in my cellar.  Wasting beer is all you're doing.

 

We have to remember we're just home brewers here.  We don't need all the chemistry and mathmatics(sp) the big boys use.  Stick with the KISS approach and RDWAHAHB.  Let that beer sit in the fermenter for three weeks. It's done.  Bottle it.  Let it condition in the bottles for four weeks.  They're ready to chill.  Chill them for three or four days.  They're ready to drink.  Do so.  Don't worry about what the ABV is.  It is what it is.

 

Worry now about getting your procedures down.  After you get a few batches under your belt where everything goes as planned when planned then you can move on to the next level and work at getting those procedures down.  Then move on to the next level after that and on and on.

 

As long as you stick to the 3 week fermentation and four week conditioning and all of your procedures are followed correctly you'll make excellent beer.

 

What Chuck N says makes good sense except that in practice it is not self evident that three weeks always and invariably results in a finished fermentation. If it does not and if the beer is still fermenting in the bottle then adding the appropriate amount of sugar to prime may in fact result in over carbonating the beer. It doesn't matter whether you are a home brewer or a professonial brewer, allowing beer to ferment in the bottle measn that you have no real control over the level of carbonation...

I agree with both of y'all. When making a new brew I'm all about the numbers and hydrometer checks. You don't know what they're going to do. My "house brews" on the other hand I only take the pre boil and post boil gravities so I can figure my efficiencies. I can tell by the color, smell, and the taste(I take a shot glass full) if it's ready to bottle.  Of the two ways I prefer the rdwhahb brewing. It's easier on me, less stressful and so is better for the brew it's self. What I'm saying is young brewers and people making new brews. Losing the sample amount sucks at bottling. However it also gives invaluable information, and with the drinking of the sample(s), experience. After you've made it 5,6,7 times you'll not need to take as many samples and tasting the samples will actually start conveying meaningful information.

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If I can make a personal suggestion here?  Forget the hydrometer.  I have one and I use to use it religously.  It now collects dust somewhere in my cellar.  Wasting beer is all you're doing.

 

We have to remember we're just home brewers here.  We don't need all the chemistry and mathmatics(sp) the big boys use.  Stick with the KISS approach and RDWAHAHB.  Let that beer sit in the fermenter for three weeks. It's done.  Bottle it.  Let it condition in the bottles for four weeks.  They're ready to chill.  Chill them for three or four days.  They're ready to drink.  Do so.  Don't worry about what the ABV is.  It is what it is.

 

Worry now about getting your procedures down.  After you get a few batches under your belt where everything goes as planned when planned then you can move on to the next level and work at getting those procedures down.  Then move on to the next level after that and on and on.

 

As long as you stick to the 3 week fermentation and four week conditioning and all of your procedures are followed correctly you'll make excellent beer.

 

It is hard not to agree with this. All of MrBeer recipes and refills state their abv and such. Unless you go all crazytown, Mad Scientist, is it needed? I have one. I just made my first partial grain brew, I thought I needed it to know what I have. But really, all of the ingredients state the approximations. 

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But the measurement is not about knowing what your ABV or final gravity is as much as it is knowing with some certainty that the fermentation has ceased. You bottle when the yeast is still producing CO2 then you risk at best gushers the next time you open a bottle. At worst, (especially if you use glass bottles) , there is a risk of exploding bottles. As a wine maker I am not so concerned about returning a sample to the bottling bucket (Not sure I would add it back to the fermenter if it is beer) and drinking it is always on the cards... but in any event, if the sample shows that the beer is ready to bottle I would simply add that sample into one bottle and mark the label on the bottle accordingly (I really want to take two or three samples over several days to make certain that there is in fact no further drop in gravity... )

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As always with homebrewing, it comes down to your preference.  I want to know the ABV of my brews.  Not because I care about getting buzzed (outgrew that a few decades ago), but to understand the potential impact on a person drinking it.  A 4.1% brew hits someone much differently than a 6.2% brew.

 

I care about OG because I want to know if I hit the recipe.  Keep in mind that Mr. Beer base refills state 3.7% ABV.  Good luck hitting that.  More like 3.1%.  Therefore, when a recipe says a specific ABV, keep in mind that it may be overstated.  If you do a recipe from elsewhere, you may do something a bit different than they did and totally miss their numbers.  Good to know that.  I dump my OG reading back in when I aerate the yeast, having sanitized both the hydrometer as well as the tube.

 

I take FG for a few reasons.  As stated, I want to know what ABV I am at, so I need FG.  Second, I want to know if the brew is done.  Since I wait 18 or 19 days to take the reading, I know with virtual certainty that it is done.  If I hit my target (use 25% if you don't know what it should be), then I know it's done.  If I made the recipe before, and I hit the OG, I know I should hit the FG.  I don't take two readings unless something is out of whack.  I do not dump the samples back in, I inevitably spill them into my mouth.  

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So I took a sample. Observations is the wort is still very cloudy, and a good amount of tiny bubbles in the sample cylinder.

 

3/11 OG 1.041

3/22 SG 1.015

 

This would give me a current ABV of 3.4%. So based on the target of 4.7% ABV. And the FG from my first batch of Aztec which was 1.012, is it safe to expect that since my Aztec hit a FG of 1.012 that the Aztec Deluxe with an LME added should also hit a FG of 1.012?

 

 

 

Took another sample tonight, I decided to wait 72 hours

3/25 SG 1.011

 

It does indeed sound like you should expect this FG to drop down another 4 or 5 points.

 

Did I see somewhere that you can figure out your target FG by taking your OG * .25 so for me it would be 1.010?

 

At this point my plan is to take another sample Friday night and if it hasn't changed place the LBK into the fridge for a 2 day cold crash then bottle Monday Night. That would give me 19days total for fermentation.

 

Sound OK? Comments?

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FG at 25% is a guideline. Every yeast works differently and is different on each batch. Yours is very close AND you learned that 3 days ago it was not finished.

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