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Old 04-19-2009, 09:05 AM   #1
OnIslandBrewer
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Default Final gravity reading without hydrometer

I know you can use a hydrometer to tell you when your fermentation is complete, but bare with me here as I'm a newbie to brewing:

Instead of having to constantly pop the lid and take your readings, why couldn't you use a balloon to let you know when final gravity has been reached? After activity slows down in the airlock, simply attach a balloon to the top of the airlock. If it inflates even slightly, you're not done yet. Pop the balloon off and repeat tomorrow. When the balloon fails to inflate over a 24 hour period, you're done! ... right? Or does the fermentation continue far past the point where noticeable amounts of CO2 are released?

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Old 04-19-2009, 12:09 PM   #2
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The problem is that CO2 isn't a reliable measure of fermentation. Yeah, the initial ferment is quite vigorous, and lots and lots of CO2 is devolved. As fermentation slows, less CO2 is devolved. But some still stays in the beer, and the weirdest things can cause it to devolve, like barometric pressure or slamming a door in the house. What I'm saying is that the ferment can be completely over and the beer can still 'off-gas'.

Moreover, there is no growth in rushing the beer out of the primary. Commercial breweries get the beer out of the primary quickly because tank space = money. But we don't need to do that. Keeping the beer on the yeast for a week beyond the end of that initial vigorous ferment has a number of beneficial side-effects.

I'm afraid that, if you want to do things properly, you're just going to have to keep using your hydrometer.

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Old 04-19-2009, 01:34 PM   #3
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using a hydrometer isnt that much of a pain anyways. I keep a bottle of starsan in a spray bottle. I then spray my thief down (takes only a few seconds) dip it in the fermenter and pour it out to measure my gravity. I only measure it after a couple weeks. No matter the gravity I leave it there for a few weeks longer. That test is more an excuse to taste my beer and see how it tastes. After a month I take another test.

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Old 04-19-2009, 01:38 PM   #4
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Also, just because "fermentation" stops, it doesnt mean that the brew is done. Read the bottle bomb threads.

Your beer could stall at 1.020 (the curse) and so you attach your balloon and decide to bottle.

You bottle, rouse up the yeast, place the bottles in a nice warm place and wake up some evening to beer exploding all over your floors and walls. Using a hydrometer is much easier than dragging out the carpet cleaner after a round of "beer mortars".

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Old 04-19-2009, 02:17 PM   #5
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You don't have to "constantly" check your grav....many of us leave our beers in primary for 3-4 weeks, and in my case I take an og reading on brewday, and then take a final grav reading a month later when I go to bottle...

If you use a secondaary, all you need to really do is take on on the 14th day (If I secondary I secondary after two weeks) fermentation should be stopped before you rack anyway, and it usually is after two weeks.

Just like an airlock is not an accurate fermentation gauge, neither would a ballon...the presence of lack of excess co2, which is what makes the balloon expand or an airlock bubbles, has no direct coorelation to fermentation activity....many people see NO airlock activity (like myself) during the course of many of their normal fermentations...

The hydrometer is really the only way to know where you at in terms of fermentation....And properly sanitized and being careful will not do anything bad to your beer...if that were the case, books and websites wouldn't advocate it would they?

Our beer is a lot hardier than most new brewers believe it is...take a read in here and you will see...

http://www.homebrewtalk.com/f39/what-some-mistakes-you-made-where-your-beer-still-turned-out-great-96780/

If you can put an unsanitized body part in a fermenter and have the beer survive, you can stick a sanitized turkey baster or winetheif in there a couple times with no problems.

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Old 04-19-2009, 03:01 PM   #6
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If you feel the need to constantly check the gravity, just take your first sample after pitching the yeast and set the tube next to the fermenter. That way you can sit and watch the gravity drop.

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Old 04-19-2009, 07:18 PM   #7
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Not that satellite fermentation ever works, but if it makes you feel better...



+1 to Revvy. I only ever really monitor my ferment if I'm using a yeast I know is lazy, like Ringwood. Otherwise, it's pitch the right amount of yeast and fugeddaboudit.

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Old 04-19-2009, 09:00 PM   #8
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Thanks for all the advice guys. Back to the hydrometer it is!

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Old 04-19-2009, 09:26 PM   #9
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I didn't see anyone mention this, so if its a repeat, I apologise.

CO2 is dissolved into your beer naturally during fermentation. Moving the fermenter and warming it up could cause the residual CO2 to escape. Just another reason airlocks aren't a good measure of fermentation.

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Old 04-19-2009, 10:26 PM   #10
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Quote:
Originally Posted by Edcculus View Post
I didn't see anyone mention this, so if its a repeat, I apologise.

CO2 is dissolved into your beer naturally during fermentation. Moving the fermenter and warming it up could cause the residual CO2 to escape. Just another reason airlocks aren't a good measure of fermentation.
+1 to this....

Another thing that people don't think about for the other extreme, when bubbles suddenly stopped.....if you opened the lid, or removed the stopper to take a grav reading, or just because you were nosey (it does happed) you will void the excess built up CO2 as well..there will still be a cushion of co2 protecting your beer, but again, the airlock is merely a vent, for any excess built up CO2...to keep you from painting your ceiling with your precious beer.
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