Are DIY CO2's "aftereffects"... potable? - The Planted Tank Forum
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post #1 of 9 (permalink) Old 09-30-2013, 06:15 AM Thread Starter
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Are DIY CO2's "aftereffects"... potable?

I imagine I'm coming across as a bit dense here. xD

On the DIY CO2 builds using yeast and sugar, after the yeast dies, there's still some sugar left in the bottle in addition to water and alcohol. I was curious if this is ethyl alcohol and safe(-ish) for consumption. I know that there's a concern when brewing moonshine and such at home that some batches have a high methanol content, which is extremely toxic, possibly lethal (so I absolutely DO NOT suggest you just "try it out").

Obviously, I'm not advocating underage drinking or brewing alcoholic beverages at home if it's against the law where you live (please familiarize yourself with any local laws regarding the matter).
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post #2 of 9 (permalink) Old 09-30-2013, 09:26 AM
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post #3 of 9 (permalink) Old 09-30-2013, 11:31 AM
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Check out this link.
ultimate DIY CO2 with benefits… wine byproduct!
I wouldn't mind knowing the answer to this as well. I notice that he only uses 1 cup of sugar but I think that is because he is using .5 liter bottles and any more sugar would affect the sweetness of the final product.
Also, I can let u know in another week when my first bottle is done.
Btw, when they make wine they just let fruit ferment in a big bucket. I would imagine there is some sugar left over once the yeast dies, so I would say its fine. But I m no expert.

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post #4 of 9 (permalink) Old 09-30-2013, 05:28 PM
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You can drink it, it will get you drunk if you drink enough of it, assuming you CAN drink enough of it, but unless you are setting it up specifically for the end product, it is going to taste pretty horrible.
Bakers yeast isn't selected for the flavors of a fermented beverage like a wine or beer yeast is. Also, unless you are sanitizing the fermentation vessel and the sugar mixture that is going in it, there are wild yeast and bacteria strains in there that may give you some funky flavors (desirable in sourdough and certain types of Belgian beers). Ask most of the people that have tried fermenting fresh pressed cider with baking yeast what the final product tasted like.
There may be sugars left over, but it is the non-fermentable sugars that give other fermented beverages their body and some of the flavor compounds in addition to the sweetness. Some sweeter wines and meads do have sugars in excess of what the yeast can consume before being killed off by the alcohol. Sulfites are added to kill off the yeast and stop fermentation in some wines, as well as to prevent other organisms from getting a foothold and altering the final product.

Bread yeast is not as alcohol tolerant as those selected for alcohol fermentation, so the content may be lower, forcing you to down more of the swill. It also isn't selected for its flocculation properties, so more of it will tend to stay suspended in the solution giving a strong yeast flavor.
Unless you are using one of the more exotic mixtures that use jello mix or something else that will have strong flavors, there isn't much to counter the yeast, alcohol, unfermented sugar combination, which is not a very pleasant taste. Ever have an unhopped/unbittered beer? Its taste is not well suited to our modern palates.

You can try using a brewing strain of yeast, but unless you modify the solution it still isn't going to taste very good. Now this is all subjective since some people will drink anything as long as it gets them drunk.

As far as the methanol in moonshine goes, that is because the distillation process concentrates the alcohol (the whole point of distilling). The methanol evaporates off at a lower temperature (before the ethanol, which evaporates at a lower temperature than water), which is why the first runnings are discarded. If someone is doing it all by feel, they are guessing when the methanol has finished and when the ethanol has started, which is where part of the danger comes in. There are also those that add stuff to give the shine more of a kick (sometimes intentionally leaving the methanol, or a portion of it, in), which comes along with an inferior product that has too much water carried over in the distilit. They need to cover up for the low quality product.
So you don't need to worry about the other alcohols that are produced during the fermentation. You would end up with alcohol poisoning from the ethanol before the other stuff causes an issue.

If you are really interested in having a finished product that is drinkable, look into homebrewing and home wine/mead making. You'll have something worthwhile, but unless you have a large tank and brew every week it may be more trouble than it is worth. But then you also have to consider how a pressurized fermentation effects the flavor of the final product. Don't forget about ambient temperature effects either.

If the thread above is the one I am thinking of, if you were looking for something that would be passable for a fruity, sugary wine, his process would be the way to go (not intending for that to be insulting. For the work and ingredients going into it, it should be decent as long as you maintain good sanitation standards. I just don't think it would be comparable to a full wine kit or wine pressed from fresh grapes. But that is a completely different animal).

aaaaaand.... now I'm late for class.

I usually feel kind of guilty using the quick reply... my replies are rarely quick.

Last edited by Beer; 09-30-2013 at 07:11 PM. Reason: cleaned it up a bit now that I'm not trying to rush to class
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post #5 of 9 (permalink) Old 10-01-2013, 06:09 PM Thread Starter
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Thanks for the replies, everyone. It was all very informative. Good to know that the more dangerous alcohols only result from distillation (which I don't plan on anytime soon).

I generally buy cheap, fruity wine anyway, so I guess this wouldn't be such a bad experiment. I also have the luck of living near a winery that sells the supplies to make your own wine, so I'll see how it goes.
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post #6 of 9 (permalink) Old 10-01-2013, 08:09 PM
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if you want to drink what your ferment, treat it as if you're homebrewing. sterilize everything.

i'd recommend, for something easy, 100% juice w/ some wine or champagne yeast.

further, you're going to want a checkvalve in place to ensure there is zero backup into the fermentation chamber. this is beyond the normal airlock you'll be required to use.

the cleaner, and free of bacteria, air, etc, you keep the fermentation chamber the better the end product will be. I'd suggest maybe make some mead. the high sugar content, so generally higher alcohol content, should mean more CO2 production over a longer period of time. you may have to rerack.

Last edited by Darkblade48; 10-02-2013 at 03:28 PM. Reason: Watch the language.
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post #7 of 9 (permalink) Old 10-03-2013, 05:09 AM Thread Starter
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I was going to go with easy, to start. The winery nearby sells various types of yeast and their own grape juice. Can't get much simpler than that.
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post #8 of 9 (permalink) Old 10-03-2013, 05:15 PM
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One of my other hobbies is home brewing.

Typically that's not sugar at the bottom. The yeast won't die until the sugar is consumed. It's probably dead or dormant yeast.

I wouldn't suggest drinking the by product. As suggested by "Beer", its going to taste pretty bad. I would be really careful, that much sugar in might create a pretty potent product. The other issue to think about is if you started with a sterile environment.

Brewing needs to be very consistent. Clean, specific temp for fermentation, exact measurements of yeast/sugars (difficult in really small batches).

As cool as I think this idea is, my suggestion, if you want to brew, brew. But I'd keep these two hobbies separate.

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post #9 of 9 (permalink) Old 10-03-2013, 06:35 PM
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I imagine if you are looking for something to drink, it would probably make more sense to start home brewing, and piping off the excess CO2 from that to your tank. It won't be as effective as tank-specific DIY CO2, but there is a much better chance that the end product will be drinkable.

Also take a look at some of the troubleshooting/problem solving stuff for home brewers, a lot of factors that aren't a concern for CO2 production can cause off-flavors in beer (or wine, I assume)
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