Alcohol content

[Badhibit]

I have read that if you take a cup of wine. Take aSG reading. Boil off the alcohol. Take a new reading of SG. And you can get the alochol content. Any other way? Whats a GOOD and accurate meter to buy? If there is one. Badhabit Edited by: Badhibit

 

[jsmahoney]

I'm not for sure if I'd want to boil my wine. I figure if you drink a bottle of wine and can't get up, it has a high alcohol content!

 

[sangwitch]

That's the method I usually use jsmahoney!


I would love to know how to determine exact alcohol content. SG readings are approximate. There has to be a scientific way (PeterZ?). Where did you read the article about boiling?

 

[masta]

The best way to get an fairly accurate reading of the alcohol content is to take a starting and ending SG when making the wine and calculate the ABV potential. I don't believe there is a easy method or inexpensiveequipment to test the finished wine for the home winemaker.


A colleague of mine brewed beer years ago and he was able to bring in a sample and have the lab run it for ABV. The testing was gas chromatography head space anda GC unitruns around $200,000.00.

 

[scotty]

i use the beginning and end SG because it is a proven method.


THE FOLOWING IS SOMETHING I AM TOYING WITH IF I EVER BUY A REFRACTOMETER




Measuring Alcohol And Residual Solids
in Wine
by Werner Roesener
This is an easy method, yielding instantaneous results of the alcoholic strength as well as residual solids (sugar) in finished wine.
Equipment required:
1. A narrow range hydrometer (SG 980 - 1022), Note 1
2. A refractometer, calibrated for 0 - 32 Brix
The method is based on the scientific facts that the gravity of wine is affected by alcohol in one direction (lighter), and by sugar solids in the opposite direction (heavier). The refractometer, however measures the optical bending of light traversing through a wine sample, and both sugar and alcohol produce readings in the same direction (increased brix reading for both).
The procedure is to take a hydrometer reading, record the SG , then to place a small drop of wine on the refractometer prism and record the resulting brix reading. Those two numbers are then placed into the following formulae to obtain alcohol and solids content.
Alcohol (vol %) = (B * 4.16 - SG + 1000) * 0.365
Solids (g/L) = (SG - 1000 + ALC * 1.264) * 2.52
Where SG is in 3 or 4 digits, ALC is in vol %, B is the brix reading. To expedite the calculation, the formulae can be entered into a programmable calculator (Note 2), or into a PC program in BASIC, C or PASCAL. It should be kept in mind that solids are made up of mostly sugar, but also the acids and other minor solid components in wine. When dealing with sweet wines, pretty near all of the solids can be assumed to be sugar. The measurement accuracy is affected by temperature. It is essential that all involved items are stabilized at the same temperature, preferably in the 15 - 18 degree Celsius range. I have been asked if the method would be suitable for following the fermentation progress. In principle, yes, but the cloudiness of fermenting wine blurs the refractometer reading, making it difficult to obtain meaningful numbers.
----------------------------------------------------------
Here is a numerical example:
A port wine produces these readings: SG 1022, Brix 18.3
Calculation results: 19.8 % alcohol, 118 g/L solids

 

[PeterZ]

Gas chromatographs aren't that expensive any more. George could set one up in the shop for $30k easy. Then we could just send samples. 1 cc is more than enough. The GC itself only takes about 20 microliters.

Distillation is difficult, because under normal conditions, without an azeotrope you cannot get the alcohol up to 100%. That's why automotive ethanol is sold at 85%. Getting the last little bit of water out is tough. Accurate specific gravity of an alcohol/water mix is possible (see below), and will give you % alcohol by weight. Converting that to %abv is complicated by the fact that 50 ml ethanol + 50 ml water gives < 100 ml. (Think of 50 ml marbles + 50 ml sand.) Someone has probably worked out a conversion table, though.

Highly accurate specific gravity is pretty easy. You can buy hygrometers much longer than the ones we use that stretch the scale out for greater accuracy and precision. That uses a lot of wine, because you need a very tall flask, too.

The other way is to do what industry typically does. You can buy extremely accurate 25 ml flasks, individually calibrated (~$100), and tare them and fill and weigh on a balance capable of reading +/- .0001 g (~$3000 used). Of course, that needs to be done in a temperature controlled environment at 68F/20C (`$???)

To me, that level of precision is not needed. Remember the difference between precision and accuracy. Precision is measuring abv to 12.847%. Accuracy is measuring 12.8% when it is really 12.6%. Neither is vital. What we want is consistency. If we make a batch of Amarone and our calculations say it has 12.8% abv, and our palate says the wine has the perfect balance of alcohol and acidity, do we care if the abv is 12.8%, 12.6%, or 13.0%? I don't. As long as we are consistent in our technique, our 12.8% on the first batch is the %abv that reads 12.8% on the second batch.

What I care about is that if I measure the samy way every time - if I am consistant, and the kit manufacturer is, too - then I know that if my next batch of Amarone also calculates out to 12.8% abv, then the balance of this batch will be as good as the last. The same applies to the fruit wine maker calculating abv by before and after sg, and testing TA.

Thus ends Episode 2 of Science You Don't Really Give a S@#% About..

 

[Badhibit]

Thanks PeterZ, I wish I had asked you in the first place. If I had knew it was that EASY. I wouldn`t have had to read a book.

 

[Badhibit]

Sangwitch, The book I have been reading is; The Art of wine making. By S. Anderdon. Lot of good info for someone like me that started making wine on a whim. Iknow of noone that makes wine my area. You cannot buy or getequip. here. The reason I wanted to know. Some of the folks here, I have given wine to says that some of it is a little to strong of alcohol.

 

[Badhibit]

WOW, I`ll learn to make a GOOD SG reading the next time I set up a batch. I had a problem from the get go masta. I think my fruit was not ripe enough. I was trying to beat the bears to the grapes. It was hard to get the SG up to 1.070. Badhabit

 

[Badhibit]

sangwitch, The book says to take 1 pint (exactly) of wine, Check the SG. Put in pan boil until 1/2 the volume. That will boil away the alcohol. Add distilled water to bring it back up to 1 pint. Check SG again to get Alc. content. Says as accurate as a (ebullioscope, about $70?) But much more so than a vinometer. Which is okay for dry wine. But not sweet wine. I have no idea what a ebullioscope is. Badhabit Edited by: Badhibit

 

[sangwitch]

To me, that level of precision is not needed. etc, etc...

very well put Peter. I would like to know the precision if it was easy and cheap, but strictly out of curiosity. When George writes that check for $30K I'll send him some examples.

I take SG readings and calculate abv to usefor the next batch. Like you said, if it's a perfect blend then I want to try and recreate it and if my taste says that the alcohol is low, I'll bump up the starting SG the next time, etc.


I'm more curious about knowing why the different calculation methods can be off a few percent. I have chosen a calculation that I use all the time for consistency, but I would still like to understand the science behind the math.


so when are you coming tothe Rock?

 

[sangwitch]

Sangwitch, The book I have been reading is; The Art of wine making. By S. Anderdon. .

thanks badhibit...


I haven't read that one yet. I have "From Vines to Wines" by Jeff Cox and "The Home Winemaker's Companion" by Gene Spaziani.


I bought the second book because I happen to know Gene and the first because of reviews I've read.


I will check out "The Art of Winemaking".

 

[scotty]

a few months go I purchased a precision hydrometer to test the ending SG. Its easy to read because itis designed to test less of a range.
At any rate, precision is not what I'm looking for either.


Its the enjoyment of playing chemist while I indulge in one of my favorite hobbies.Edited by: scotty

 

[Badhibit]

Thanks scotty, Not knowing what I was doing, when I stated making wine? I didn`t know much about SG. I didn`t put in enough sugar to bring up the SG high enough. I have added sugar twice since mush. To sweeten. And itstarted working anew?I do know the alcohol SHOULD BE at least 9% to protect the wine. That was my only concern. Not if it will knock me on my rear or not. LOL I didn`t want to cause anyone to get carpal tunnel? Or what ever you call it.

Badhabit

 

[scotty]

Please tell me about this mush business. I havent a clue and would really appreciate the whole anchilada.

This is the most interesting hobby i have ever gotten sucked into.
With all the experienced folks and those with the real technical information we all should be able to become better and better.
Excep for __________

Im also wondering why you shoot for 9%. I understand that that is the bare minimum and it seems a little risky to me especially considering the chemistry lesson on accuracy that peter gave us.Edited by: scotty

 

[Badhibit]

scotty, The making of must is kind is when I put the clean grapes in a stone crock, 10 gal. Or a 5 gal. food grade bucket, with lid. I crush the grapes with a8 inch long pice of wood 4X4 with a handle. Like broom handle, NO PAINT. Do not crush the seeds. Makes the wine bitter. Test acid and SG. Which I didn`t do.

Ajust acid to 65%, with acid blend. And ajust SG to1.095 with sugar to bring UP. Or water to bring DOWN. Add 1 ounce of metabisulphite, or 1 campan tablet per gal. Check temp. keep temp between 70 & 80. In about 24 hours. Try to have must at ideal Temperture 75 degrees. Add yeast. cover with plastic. Stir down every 24 hrs. Let set 3 to 6 days. 48 hrs= light red wine, 5 to 6 days= dark red. I set mine about 3 days. Strain into carboy. scotty, You need to keep the wine above 9% to keep it well. Wine below 9% can spoil. Badhabit and Thanks I have read ITS posible to get wine to 21%Edited by: Badhibit

 

[scotty]

Thanks scotty, Not knowing what I was doing, when I stated making wine? I didn`t know much about SG. I didn`t put in enough sugar to bring up the SG high enough. I have added sugar twice since mush. To sweeten. And itstarted working anew?I do know the alcohol SHOULD BE at least 9% to protect the wine. That was my only concern. Not if it will knock me on my rear or not. LOL I didn`t want to cause anyone to get carpal tunnel? Or what ever you call it.

Badhabit

This is what I was asking about

 

[PeterZ]

sang,

I really don't know the background of the different calculations, and cannot speculate about which is the most accurate. Possibly the more complex factor in the effect of other wine chemicals, acid, etc. while the simple one is based on sucrose in distilled water.

Personally, I use the (initial SG - final SG)/factor (whatever masta said) because it is easy.

 

[scotty]

sang,

I really don't know the background of the different calculations, and cannot speculate about which is the most accurate. Possibly the more complex factor in the effect of other wine chemicals, acid, etc. while the simple one is based on sucrose in distilled water.

Personally, I use the (initial SG - final SG)/factor (whatever masta said) because it is easy.

Ill stick with that method too pete. Please understand that the chemistry thing is fascinating me and thats whats driving me to drink

 

[Badhibit]

Sorry scotty, But its called MUST. Badhabit