Calculating Alcohol Content

[jody]

I am on my second wine kit at the moment. It is my understanding that in order to calculate the alcohol content you must take the specific gravity just before adding the yeast and then again before you siphon into the secondary fermenter. And take the difference in the readings. I am wondering if this is correct?

I have the brew belt on my primary fermenter right now to aid the fermentation. I have been told that after the wine goes into the carboy (second stage) my basement temperature of 15C (59F) will suffice for this stage. Is that correct?

 

[cpfan]

I am on my second wine kit at the moment. It is my understanding that in order to calculate the alcohol content you must take the specific gravity just before adding the yeast and then again before you siphon into the secondary fermenter. And take the difference in the readings. I am wondering if this is correct?

I have the brew belt on my primary fermenter right now to aid the fermentation. I have been told that after the wine goes into the carboy (second stage) my basement temperature of 15C (59F) will suffice for this stage. Is that correct?

Hi Jody...

1. Not quite correct. Starting sg is prior to pitching the yeast. Ending sg is prior to stabilizing the wine (ie adding the K-meta and K-sorbate). The sg may drop further once the wine is in the carboy.

2. IMO, wrong. I make my wine kits all the way through clearing at about 24C (74F). Once it's clear and into the bulk aging stage, I may let the temperature drop depending on what other wine/beer is in the room. I think that RJ Spagnols instructions suggest a drop in temperature at some point. Winexpert and Vineco do not.

3. Degassing will be very difficult (nearly impossible?) at 15C. Keep it up to about 24C until the wine is degassed and clearing.

Steve

 

[Dugger]

Just to add to what Steve said, the alcohol content is calculated by subtracting the finish SG ( when fermentation is completed) from the starting SG and then multiplying that by 133.
eg starting SG is 1.085; final Sg is 0.995 ... alcohol content is 1.085 minus 0.995 = 0.090 x 133 = 11.97 or 12%

 

[Minnesotamaker]

If you're lazy like me, take your S.G. reading before you pitch the yeast and again when the wine is done fermenting. Plug the two numbers into the calculator on this website and it'll give you the alcohol content.

LINK -----> WINE MAKING CALCULATORS

 

[Charlietuna]

Just to add to what Steve said, the alcohol content is calculated by subtracting the finish SG ( when fermentation is completed) from the starting SG and then multiplying that by 133.
eg starting SG is 1.085; final Sg is 0.995 ... alcohol content is 1.085 minus 0.995 = 0.090 x 133 = 11.97 or 12%

When I started(in May of this year) which says I'm a rookie. I read that the calculation was (Starting SG - Finished SG / .0074) It's close & probably doesnt matter, but does anyone have an official equation?

I think my calculation came from a wine book I got from the local wine shop.

In the above calculation the difference is 11.97% abv or 12.16(by what I read), which means nearly nothing.

Thanks,

Brian

 

[Dugger]

Dividing by 0.0074 is the same as multiplying by 135, so it's basically the same equation. The numbers vary from winemaker too winemaker - some use 133, some 131.something, and in your case, 135. As you say, they all produce a number that is close enough that it really doesn't matter.

 

[jody]

Thanks everybody for the replies

Hi Jody...

1. Not quite correct. Starting sg is prior to pitching the yeast. Ending sg is prior to stabilizing the wine (ie adding the K-meta and K-sorbate). The sg may drop further once the wine is in the carboy.

2. IMO, wrong. I make my wine kits all the way through clearing at about 24C (74F). Once it's clear and into the bulk aging stage, I may let the temperature drop depending on what other wine/beer is in the room. I think that RJ Spagnols instructions suggest a drop in temperature at some point. Winexpert and Vineco do not.

3. Degassing will be very difficult (nearly impossible?) at 15C. Keep it up to about 24C until the wine is degassed and clearing.

Steve

Day 14 which is labelled "Stabalizing/Degassing" in my kit instructs the addition of Potassium Sulfite, Potassium Sorbate, and Kieselsol (after transferring to carboy). So should I take sg after transferring to carboy and before adding these additives? And that would be my end sg?

Day 15 which is labelled "Clearing" in my kits has me adding Chitosan.

So from what I gather degassing will take longer than that one day(hence the airlock letting gas out). Also clearing will take some time as well.

How will I know the wine is completly degassed?

Transferring into the carboy should take place when the sg is 0.995 or less (according to my kit). Okay I got that part but how will I know when I can filter/bottle the wine. Should I just wait the two weeks in the carboy as the kit instructs (it is a 4 week kit)?

As for keeping the temperature up, my wine belt says I can only run it for 8 days and not to use it on glass carboys. Puts me in a pickle as my basement only maintains 15C(59F).

Thanks all for the calculation equations, etc.

 

[tjbryner]

Thanks everybody for the replies




Day 14 which is labelled "Stabalizing/Degassing" in my kit instructs the addition of Potassium Sulfite, Potassium Sorbate, and Kieselsol (after transferring to carboy). So should I take sg after transferring to carboy and before adding these additives? Yes take an SG reading And that would be my end sg? Your ending is SG will be when the SG stays the same over a 3-4 day time span, something below .999

Day 15 which is labelled "Clearing" in my kits has me adding Chitosan.

So from what I gather degassing will take longer than that one day(hence the airlock letting gas out). Also clearing will take some time as well.

How will I know the wine is completly degassed? Do you have a de gassing tool? basically your wine will clear really fast when degassed completely

Transferring into the carboy should take place when the sg is 0.995 or less (according to my kit). Okay I got that part but how will I know when I can filter/bottle the wine. Should I just wait the two weeks in the carboy as the kit instructs (it is a 4 week kit) ?you will filter when all the sediment has dropped out of suspension, I don't believe in these timelines as every one has different temps and conditions. Think of of them as a guide not as a rule

As for keeping the temperature up, my wine belt says I can only run it for 8 days and not to use it on glass carboys. Puts me in a pickle as my basement only maintains 15C(59F).many people here use them on glass I'd think you would be safe to do the same.

Thanks all for the calculation equations, etc.

I put my 2 cents in bold for each question, just remember Time is your friend and best tool when making wine. I have a 4 week kit going on week 6 just setting there waiting to degas on it's own.

 

[mmadmikes1]

Dont put it in basement at 59 degrees. It will not degas and will not clear

 

[jody]

I put my 2 cents in bold for each question, just remember Time is your friend and best tool when making wine. I have a 4 week kit going on week 6 just setting there waiting to degas on it's own.

For taking readings of sg to watch for it staying the same over a 3-4 day period should I start taking the sg after adding to the secondary carboy and just keep checking daily?

I am thinking of buying degassing tool that connects to my drill. Last batch(first time) I did a red wine so I found a didnt get a clear picture of when it was cleared. I did give it an extra week in the carboy and racked it an extra time that the kit did not call for. This batch of white I am not so patient as I have almost run out of wine from the first kit.

So if I understand you correctly I will know it is degassed when the wine is clear? And is that when I can bottle (i.e the sg is staying the same and the wine is clear)?

I do understand taking my time and racking will make the wine taste better. But as I said I am in a hurry for this batch.

Also I heard of a 7 day accelerator from Wine Kitz. Is this something that will speed up the process? And is this reccomended? I know at this point it is to late for my kit (for the accelerator) I have on the go which is only 5 days in the primary.

 

[LJPelletier]

Dave Miller estimates the alcohol by volume using a very simple formula in his book “The Complete Handbook of Brewing (1988)”. Simply subtract the final gravity reading from the initial gravity reading, and then divide by 0.75.

Alcohol by Volume = (Initial Gravity - Final Gravity) / 0.75

 

[cpfan]

Dave Miller estimates the alcohol by volume using a very simple formula in his book “The Complete Handbook of Brewing (1988)”. Simply subtract the final gravity reading from the initial gravity reading, and then divide by 0.75.

Alcohol by Volume = (Initial Gravity - Final Gravity) / 0.75

Are you saying that is simpler than
Alcohol by Volume = (Initial Gravity - Final Gravity) * 133

I prefer the multiplication over the divisiom because I think that many people understand multiplication better than division

Alcohol by Volume = (Initial Gravity - Final Gravity) / 0.75
(1.100 - .992) / .75 = .108 / .75 = .144 (ie 14.4%)

Alcohol by Volume = (Initial Gravity - Final Gravity) * 133
(1.100 - .992) * 133 = .108 * 133 = 14.364 %

Pretty much the same formula.

Steve

 

[jody]

Okay I think I was running around in circles with my questions. I took some time reading some other posts and it became clear when to take the sg readings for calculating the alcohol content.

I have more questions about degassing and clearing but I will address them in another thread.

Thanks all

 

[LJPelletier]

Are you saying that is simpler than
Alcohol by Volume = (Initial Gravity - Final Gravity) * 133

I prefer the multiplication over the divisiom because I think that many people understand multiplication better than division

Alcohol by Volume = (Initial Gravity - Final Gravity) / 0.75
(1.100 - .992) / .75 = .108 / .75 = .144 (ie 14.4%)

Alcohol by Volume = (Initial Gravity - Final Gravity) * 133
(1.100 - .992) * 133 = .108 * 133 = 14.364 %

Pretty much the same formula.

Steve

I didn't say it was simpler or harder, just sharing info. Likely 95% of those using any of those formulas will be using a calculator anyways. The other 5% will use a website that does it for ya. lol

 

[Rocky]

They are essentially the same formulas in a different format. The first example divides by 0.75 and gives ABV as a decimal which you would multiply by 100 to get a percentage. The second multiplies by 133 and gives ABV as a percentage straight away. In the first case, you are dividing by 0.75 (75/100) so you would invert and multiply by 100/75 (or 1.333...) and then multiply by 100 to get the percentage, which is the same as multiplying by 133.333... (again, an infinite decimal).

I think that pretty much beats this subject to death.

 

[mmadmikes1]

Jody wine will clear before it is competently de gassed. the shake test is put a small amount into a small bottle and shake it. if you get ANY bubbles it still needs more degassing