Alcohol in Finished Wine

Danny:

Tell us what the exact brand and kit (eg Ken Ridge Classic Holiday German Riesling) and someone can probably suggest the starting sg based on prior experience.

However, a finishing sg of 1.060 sounds wrong. Most kits finish under

1.000, actual number dependent mostly on brand. I was just looking at a white today that 's at .990.

If you sweetened it may have gone back up to 1.006.

Steve

Agree with the above. If you know the name of the company you can probably go to their web site and fine the instructions or even contact them about what alcohol level to expect. If you made it by their instructions then they can tell you within 0.5% and that is about as close as you are going to get with home measurement and calculation.

Ray

A vinometer will tell you mow much alcohol is in your wine, but it won't work if there is any sugar left. Like everyone else said, you seem to have lots more sugar left over from a fermentation than you should have. So you can't use a vinometer. Check your measurements of S.G. again. Are bubbles lifting your hydrometer up? Did your must get too cold mid-fermentation. Look for things like that to see if it explains your result.

'Danny' said he had just finished bottling ... Kits do have stabiliser... but I would be worried his bottles may go pop.

If you use the stabilizer that comes with a kit and you do it according to their instructions, the bottles will not go POP.

Ray

correct me if im wrong,,but on a hydrometer , if you measure the specific gravity before fermentation , it will tell you what the after fermentation alcohol is if fermented down to 1.00 specific gravity. best regards,lucas

That is a matter of debate. If you look in a table for the potential alcohol when you have an SG of 1.090 you will find that it is something like

12.0%. But what does this mean. Using the same tables different sources will interpret this differently. Some will say that it is the potential alcohol if the SG drops to 1.000. So if the SG drops to 0.990 (which happens, then you will have a alcohol level of 13.4%.

Other sources say than the potential alcohol is the alcohol that can be produced if the yeast consume 100% of the sugar. In this case, to get 12.0% alcohol the SG would have to drop to 0.990 and if it only dropped to 1.000 then your alcohol content would be 10.8%.

I have never found anything that indicates one source is correct and another is wrong. I guess you can believe what you like.

Add to this the fact that depending on temperature, nutrients, and other factors, yeast is more or less efficient at making alcohol and you can easily have a 0.5 to 1.0% error due to this and your error may be bigger than you think.

In other words you can be off by 2% using any calculation and when people tell you you can calculate it to within 1/2 %, ...

Ray

Hmmm, whatever happened to Frederick... ;)

I've got 2 reasons that make me inclined to believe the 2nd explanation (100% sugar consumption):

- senses: dry white started at 1.090 tastes more like it has 12% alcohol than 13.4%

- Margalit's formula Brix * 0.57 gives about 12.2% for sg 1.090, and from all the sources that write about this topic, I find his work best documented.

But it's all really academical for home winemaking. In the end, it's the taste that really matters and not the number, and after some experience, everybody will know what range of starting sg they like for their wines...

Pp

The only sure fire way to tell final % alcohol is to use a gas chromatograph or some other analytical equipment.

You can use all sorts of methods to determine "potential alcohol" like going down below 1.000 and considering that the yeast have used 100% of the sugar (alcohol and water mixtures have densities below 1.000) But even then you have a significant wrinkle. Yeast will not produce 100% alcohol from sugar. Some of it goes all the way to CO2 and Water through aerobic respiration. Other stuff gets left as congeners (distilling term, relevant to the use of a GC). The only way to tell exactally what you have is to separate out all the differnet components and then measure each one individually and quantitate each one. The GC is the method of choice (becasue it separates out each species before quantitation) but there are other ways to do it. You can measure alcohol chemically using dichromate, but then you have to worry about all the "other stuff" interferring on the assay. I do not know how wineries do it. But I think the dichromate assay requires you to distill the wine first for accurate results. I beleive that most wineries jsut use a fancy hydrometer called a pycnometer or send samples off to be quantitated via the dichromate method.

Of course, most wineries cannot afford a CG, they are not extrememly expensive... it has been a while since I priced them they might be had for $50,000 or so, but the cost to run them is high. Of course a real neat setup would be a GC/MS which would quantitate really easy, but they cost a bit $250,000 and I doubt it is on the list of "approved" FDA alcohol measurement techniques.

Anyway, the point is do not expect to get an alcohol measurement down to the 0.xx%. It jsut is not going to happen. As a matter of fact if you get a measurement accurate to the 2-3% range It would be more than fine.