Continuous monitoring of gravity
#1
Posted 30 May 2009 - 10:36 AM
#2
Posted 30 May 2009 - 10:40 AM
I don't have any reason to think it is or is not consistent - what makes you think this? You could definitely take some data to test your hypothesis thoughI'd imagine there's a pretty consistent amount of gas produced for every drop in gravity point. If you know precisely how much gas has been produced in your fermentation, you should know pretty precisely what your gravity drop has been.
#3
Posted 30 May 2009 - 10:51 AM
I would think it's consistent because the there is a precise amount of carbon dioxide produced for each unit mass of sugar that is converted to alcohol. The ratio of monosaccharides to disaccharides may effect the number, I'm not sure though. I still need to do some more research. I bet Basser could shed some light on the subject.I don't have any reason to think it is or is not consistent - what makes you think this? You could definitely take some data to test your hypothesis though
#4
Posted 30 May 2009 - 10:55 AM
Yeah - I can see how it could be consistent but at the same time there are a lot of variables I don't understand. I just e-mailed my friend Tyler at the Portsmouth Brewery as well as this is the kind of question he might know the answer to.I would think it's consistent because the there is a precise amount of carbon dioxide produced for each unit mass of sugar that is converted to alcohol. The ratio of monosaccharides to disaccharides may effect the number, I'm not sure though. I still need to do some more research. I bet Basser could shed some light on the subject.
#5
Posted 30 May 2009 - 11:16 AM
#6
Posted 30 May 2009 - 11:19 AM
#7
Posted 30 May 2009 - 11:26 AM
#8
Posted 30 May 2009 - 11:29 AM
Edited by JKoravos, 30 May 2009 - 11:37 AM.
#9
Posted 30 May 2009 - 11:32 AM
Good info there, thanks.I wonder how consistent the CO2 production from EMP vs. sterol would be from batch to batch?"Carl Joseph Napolean Balling studied the relations between extract and ethanol levels from an emperical point of view in order to tak into account losses that occur in real fermentations. The main los is due to the yeast cells' use of carbohydrates for growth as opposed to ethanol production. Balling's measuremens showed that:2.0665g of ferementable extract -> 1 g of ethanol + 0.9565g of CO2 + 0.11g of losses."- George Fix, Principles of Brewing Science p. 92The point of the work wasn't to use CO2 to measure gravity, but this might be a starting point for you to try. I would of course measure gravities as well in order to check to see if your measurements conform. I think his point was to get a number for how much extract would be needed to produce a certain amount of beer at a specific alcohol level. The only problem I'm not sure this actually takes into account (being empirically derived it might) is the difference in CO2 production betweeen the EMP pathway and sterol synthesis. Both processes release CO2.
#10
Posted 30 May 2009 - 11:33 AM
Uh oh....Now you could also capture the CO2 to recycle...
#11
Posted 30 May 2009 - 12:00 PM
If you keep your primary sealed up from some point onward it will carbonate itself. That's a pretty good reuse that some small breweries do.Uh oh....
#12
Posted 30 May 2009 - 12:19 PM
Yeah, I mean, for that formula, it might not even matter, it might have ended up being some sort of average based on real fermentations (which is what I think Balling was trying to do) and so he doesn't even get into the line between how/why a CO2 molecule was produced just that it was. I just wanted to get you something to work with, but my chemistry is kind of weak. Not sure why, but I've always had a mental block in chemistry compared to physics. I'd have to read more to understand how that was developed.Good info there, thanks.I wonder how consistent the CO2 production from EMP vs. sterol would be from batch to batch?
#13
Posted 30 May 2009 - 12:36 PM
Yeah, some brewing literature makes the disctinction between this and priming. A lot of homebrewers refer to priming as natural carbonation, while other brewing literature calls this method natural carbonation and keeps priming separate, especially stuff that deals with the math of the situation. Priming may or may not conform to the Reinheitsgebot while natural carbonation always does.If you keep your primary sealed up from some point onward it will carbonate itself. That's a pretty good reuse that some small breweries do.
#14
Posted 30 May 2009 - 01:18 PM
#15
Posted 30 May 2009 - 02:55 PM
#16
Posted 30 May 2009 - 03:01 PM
It would only work if you're doing open fermentation. There is slightly more pressure in the fermenting wort and the headspace than the ambient pressure. CO2 is going to come out of solution in the sight glass or be pressurized. I'm not certain how the pressure change would affect the reading of the hydrometer, but as I understand it you're supposed to degas fermenting wort/finished beer for hydrometer readings (I know I currently do this). So it might not even be a trustworthy reading if you had a hydrometer constantly floating in your fermenter even with an open fermentation.I think using a surrogate like CO2 to infer gravity through the process is a good idea. Still what I don't understand is why someone hasn't developed some sort of hydrometer that is integrated into these fancy conical fermenters. There are sight glasses sometimes built into these things. Why not have something like a port with a vertical glass tube and hydrometer. When you charge the vessel with wort the tube would fill up and you'd get your OG. Over time as fermentation progresses you'd get a continuous gravity reading. Maybe you'd need two ports running into the vertical glass tube a couple inches apart near the bottom so yeast could flocc out and wort/beer could still exchange through an open port above the trub that would form.
#17
Posted 30 May 2009 - 05:45 PM
#18
Posted 30 May 2009 - 05:49 PM
#19
Posted 30 May 2009 - 05:54 PM
It's all going to end up in the same place, right? In mah belly!!!I think it's a dumb idea because the other reason to take samples is to taste it. Not just measure the gravity.
#20
Posted 30 May 2009 - 09:17 PM
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