[SOLVED] Questions about my first batch of wine

Harry, Welcome and good luck with your first wine kit. It sounds like you are fermenting a bit on the cool side, so it might take your must longer to finish fermenting. I assume you took a starting SG/% alcohol by volume before you added the yeast? If so, what is it? This starting SG reading is your starting point. As your must ferments, the SG/% alcohol reading will go down. You'll know your must is done fermenting by how close the SG reading is to 1.000 or below. The way to determine your % alcohol by volume is subtract your ending % alcohol reading from your starting % alcohol reading, and this will give you your % alcohol. For example, my pumpkin wine had a starting SG of 1.090 and a % alcohol reading of 12 %. After fermentation was complete, my SG reading was 1.000, and my % alcohol reading was 0%. So, 12% - 0% = 12% alcohol by volume ( my pumpkin wine is 12% alcohol by volume). Hope this helps. Darlene

Harry,

The answer is in your post: you're fermenting at a cooler temperature, so things go more slowly. That's fine if you're trying to preserve the fruitiness of a delicate white, for example, but otherwise you might want to warm things up a bit. But no harm if you don't, as long as it keeps fermenting.

As to the hydrometer, the % alcohol is a prediction of the final alcohol content for a given SG/Brix. Remember that water has a SG (density) of

1.000, sugar is more dense, and alcohol is less dense. As the starting sugar content increases, so too does the the predicted alcohol content. But, as fermentation proceeds, you use up the sugar and replace it with ethanol, which is less dense. So the SG goes down as time passes & fermentation proceeds. Note that alcohol is even less dense than water (the standard for the SG scale), so that dry wines eventually end up with SG's below 1.000, such as .995 . Taking hydrometer readings during fermentation doesn't directly tell you the alcohol content, but you can get an idea of it from the drop in SG. If you divide the drop in SG by 7.9, it will give you the approximate % alcohol.

Clear as mud, right?

HTH, Mike MTM

Harry Colquhoun wrote:

Hi Mike,

Thanks for the info! It did help.

Now for a couple of follow-up questions...

Do you think there will be any negative results from the fact I used a

23L glass carboy as my primary fermenter instead of a 40L plastic pail that seems to be recommended? I didn't fill the carboy to the top (maybe 2L of air left in the carboy) and I have had it sealed with a rubber bung and airlock the entire process. I imagine I'm going to see a much slower fermentation because of the reduced oxygen available.

Yesterday I transferred the wine from the primary carboy into a second carboy (the guy at the wine store said to never leave the solution in the primary fermentor for more than 7 days). Should I have done that?

Thanks all for the replies, they are much appreciated!

Cheers, Harry

Harry,

That's perfectly OK for a non-pulp wine. As long as you don't have a mass of skins etc. to float up in a "cap", I would actually favor the sanitation & visibility of a carboy.

. I imagine I'm going to

Are you ready for yhis? If the must were _fully_ oxygenated, very little fermentation would go on at all, as the yeast would be performing Respiration instead, and little alcohol would be produced. Yeast can either eat sugar efficiently with oxygen to make CO2 & H2O, or eat it inefficiently without oxygen to make CO2 & alcohol. If they can make use of oxygen, they can reproduce rapidly & get their population numbers high. What usually happens next is they run out of available oxygen and switch to fermaetntion to process the sugar. The reason we want good exposure to oxygen in the beginning is simply to get a lot of yeast cells, which then starve themselves into fermentation. Beyond that point, there's usually very little oxygen getting into the must anyway, so the carboy probably makes little difference, especially if you had a headspace of a couple of liters.

Again, I'm sure it's fine. You might actually have speeded things up by introducing some oxygen acd giving the yeast a burst of renewed vigor. But you want to keep it under a fermentation lock at this stage, of course.

You're welcome. 'Luck Mike MTM

Not in a nomral brix must. With the high amount of sugar present, the yeast (for the most part) will not respirate even if sufficient oxygen is present. They will (primarily) still ferment. It is believed they still ferment because they detect the high concentration of sugar and fermentation is faster for them to obtain usable energy.

This is true, but they appear to favor fermentation unless there is low sugar, low alcohol and sufficient oxygen present. Then, they may switch to respiration to conserve sugar because they can obtain significant more (18 X) energy from each sugar molecule.

They will use the O2 to maintain cell health even through the high reproduction phase that happens early in the fermentation. This is why O2 early in the fermenation can speed it up. The resulting yeast cells, post budding, tend to be healthier. They can also maintain the cell health better as fermentation progresses and the alcohol concentration increases.

In practice, I agree the carboy is ok, I just don't agree with your reasons.

Andy

Thanks for the answers. I, of course, have a few more questions. :-)

So here's my problem: the wine kit I'm using says "don't transfer until SG reads 1.010 or lower". Well, I'm still just below 1.060. At the rate it's going, it could be a few more weeks until I'm at 1.010. Do I leave the wine in the carboy it is in right now, or should I be transferring to another carboy every 7 days? I understand you don't want to have dead yeast cells hanging around your wine for very long, so I'm thinking I should transfer at least once a week until I get a SG reading below 1.010.

Which leads me to my next question: each time I transfer, I lose about 1/2" of wine on the bottom of the carboy, due to the plastic tip on my siphon to prevent bottom sludge from siphoning over. I can understand throwing out the sludge when you do the first racking (with all the bentonite in there), but should I be saving and/or filtering that bottom bit on each succesive racking? Seems like a lot of wine to lose each time!

Thanks in advance, Harry

If you tilt the carboy to the side just abit (maybe a 1/2" chunk of wood under one side) and let is sit that way instead of just flat, most of the lees will be in the "bottom" edge of the carboy, and you can get more of the wine out. Expirement around with the size of wood chunk. I foud that with my one gallon jugs, 1/2 is just fine. I will probably go to an inch or so with the 5-6 gallon carboys...

email: dallyn_spam at yahoo dot com please respond in this NG so others can share your wisdom as well!

Andy,

Thanks for the additi> Not in a nomral brix must. With the high amount of sugar present, the

Are you saying that yeast will ferment instead of respiring in the presence of adequate oxygen, even at the expense of greater energy efficiency, perhaps because the pathway is shorter? I have nothing to go by, but this seems a wasteful strategy to me. My understand was that the greater energy "capture" from respiration led capable organisms to use it preferentially. Or is this not so in this case?

I have no reason to disagree. I think it adds up to what I said more briefly, doesn't it?

I'm glad we agree on the suitability of the carboy, but what reason did I give for it that you object to? I can't see where your additional info, while undoubtedly correct, makes any material difference.

In any case, Thanks for your responses.

Mike MTM

Yes. They can get 2 ATPs per sugar molecule with fermentation and

36/38 ATPs from respiration but they can "process" the sugar via fermentation much faster so when sugar is abundent, they tend to "choose" fermentation. This allows them to obtain more energy over a given time period. Think instant gratification.

When sugar is not so abundent and oxygen is present they may switch to respiration because it is more efficient, but usually in a wine/beer fermentation they don't because (it's believed) the increase in alcohol (and possibly other toxins) favor fermentation. It was "theorized" that this may be due to the yeast starting to have trouble managing the movement of molecules through the cell wall which may be easier when fermentation is occuring rather than respiration for some reason.

I just wanted to make it clear that I believe O2 is good for a healthy fermentation, even if the yeast don't use it for respiration. It's still important at the start of fermentation.

Only that the O2 was good because the yeast would use it for respiration. It's needed, but for other reasons.

Really, no material difference to the use of a carboy for primary fermentation, only clarifying how the yeast use the O2. The misconception about yeast respiring before switching to fermentation keeps rearing it's head. I think it must have come out of some home wine or beer making book(s) and has been passed around by word of mouth.

Andy