Calculating time to reduce alcohol in wine using heating method

[ArtZ]

Experiment design always requires iterations. I've worked in research labs my entire career that were well equipped both in instrumentation and labware. Now, being retired, I have no labware access and generally have to make do with what I can scrounge around the house. Your suggestion is a good one. I do plan to hobble over to the local Labpro to get some sample retention bottles with caps for later tasting.

I'll have to rethink the thermocouple positioning; I am sure I can find a way to position the TC that will be acceptable.

Several posters remarked that the process that I'm planning to use heat to reduce the alcohol in the wine is distillation. I didn't get it at first, but, yes it is though I have no interest in recovering the alcohol distillate. What I saw online multiple times is a flask with wine where the wine is heated with a Bunsen burner. The vapors are cooled to recover the distillate using a water condenser.

There is apparently no control of the heating of the wine with the Bunsen burner. The process is probably terminated when the recovered alcohol no longer flows from the condenser.

Maybe I can use my sous vide bath to do this with more precision than the butane burner and a thermocouple.

I'm not sure what maximum temperature of my ANOVA sous vide bath but I'm guessing it must be close to 100C. I probably can't use the distillation flask because I'll want pipette out a small quantity of the remaining wine at intervals to measure ABV so that I plot concentration as function of time at a fixed temperature

 

[Chestermiller]

This is follow up to my post # 54.

According to this online calculator https://www.handymath.com/cgi-bin/e...ncv=15&submit=Calculate&volwght=&calcvolwght=, for 15% ethanol by volume, the mass fraction ethanol in the wine is 12.1%. For a molecular weight of 46 g/mole for ethanol and 18 g/mole water, this breaks down to an initial mole fraction ethanol of $x_0=0.051$ for the ethanol and $(1-x_0)=0.946$ for the water. This reduces to a weighted average molecular weight of 17.1 for the wine mixture. So, if we have 250 g of wine initially (assuming a typical initial wine density of 1.0 g/cc), the initial number of moles of wine in the beaker is $m_0=14.6$.

At 80 C (assumed operating temperature), according to the steam tables,, the term $\frac{P^*_W}{RT}$ in the denominator of Eqn. 11 for the characteristic time for ethanol removal is $1.63x10^{-5}\ moles/cc$. Assuming that the 250 ml wine is contained in a 500 ml "beaker" of diameter 3", the area of the heat transfer surface is A = 45.6 cm^2. Substituting these values into Eqn. 11 of post #54 for the characteristic ethanol removal time $\tau\ (sec)$, we obtain $$\tau=\frac{19700}{7k_E-k_w}$$As noted in post #54, the mass transfer coefficients in the denominator are highly uncertain, and, because of the higher diffusion coefficient of water than of ethanol in air, the value of $k_W$ is expected to be a little higher than $k_E$. Individual k values tend tend to range from about 0.1 cm/sec too about 10 cam/sec. My best crude guess for the value of denominator of this equation would be about 4 cm/sec. Substituting this into the above equation yield a value of $$\tau=\frac{19700}{4}=4900\ sec= 80\ min$$So we are probably looking at times of 10's of minutes to hours for the ethanol concentration to be reduced to desired levels in the wine.

 

[JT Smith]

What final volume of wine is predicted by this model?

 

[Chestermiller]

What final volume of wine is predicted by this model?

For what change in the mole fraction of ethanol?

 

[JT Smith]

Wasn't the premise a reduction to about 4% ABV?

From 0.051 to 0.013.

 

[Mayhem]

Yes, that’s what I said. At 202, it is 7.5% in the liquid.

This diagram is for the binary system water and alcohol; no air.

To which degree would you say the introduction of dissolved acids and flavor compounds would change this data?

 

[Chestermiller]

Wasn't the premise a reduction to about 4% ABV?

From 0.051 to 0.013.

If we divide Eqn. 8 by Eqn. 9 of post #54, we obtain (neglecting the value of x compared to 1):
$$\frac{d\ln{m}}{d\ln{x}}=\frac{(k_W+7k_Ex)}{(7k_E-k_W)}$$Dividing numerator and denominator by $k_W$ and assuming that the ratio of the mass transfer coefficients is proportional to the ratio of their diffusion coefficients in air (i.e.. k_E/k_W=0.4), we obtain:$$\frac{d\ln{m}}{d\ln{x}}=\frac{(1+2.8x)}{1.8}$$The value of x is never larger than 0.05, so, at worst, we have $$\frac{d\ln{m}}{d\ln{x}}=\frac{(1.14)}{1.8}=0.63$$So, based on this crude approximation $$\frac{m}{m_0}=\left(\frac{x}{x_0}\right)^{0.63}=(0.25)^{0.63}=0.42$$So, as you correctly point out, to arrive at the desired reduction in the concentration of ethanol in the liquid, over half the liquid would have to be evaporated.

 

[JT Smith]

Thank you for doing the math for me.

I can't speak for the OP but I believe the idea was to remove most of the ethanol while leaving the character of the wine otherwise unchanged. In this case the wine ends up concentrated. Ignoring that aromatics will undoubtedly be lost and some fraction of the remaining flavor compounds will likely be denatured it would seem to make sense to return enough water so that the final mixture is at the same concentration of flavor components. That way a spoonful of wine in a recipe is still a spoonful of wine. Adding water would further reduce the ethanol concentration. So if 4% ABV is the target and adding some water back to return to the original volume is also desired, then the initial reduction target could be set higher. Maybe you only need to heat it until it's at 7% ABV or whatever.

 

[ArtZ]

Thank you for doing the math for me.

I can't speak for the OP but I believe the idea was to remove most of the ethanol while leaving the character of the wine otherwise unchanged. In this case the wine ends up concentrated. Ignoring that aromatics will undoubtedly be lost and some fraction of the remaining flavor compounds will likely be denatured it would seem to make sense to return enough water so that the final mixture is at the same concentration of flavor components. That way a spoonful of wine in a recipe is still a spoonful of wine. Adding water would further reduce the ethanol concentration. So if 4% ABV is the target and adding some water back to return to the original volume is also desired, then the initial reduction target could be set higher. Maybe you only need to heat it until it's at 7% ABV or whatever.

Hmm, good point about increasing the initial reduction ABV if the remaining if the the original volume is restored by adding water.

 

[ArtZ]

I received the digital refractometer on Thurs. Yesterday, I attempted the calibration of the unit. It's a simple procedure requiring only 2-3 drops of distilled water, then press the cal button. Should return 0.0% ABV on the display. Instead the unit returned different error messages on subsequent cal attempts. I'll try again today to cal the unit. If no success, I'll return it for a replacement.

I see a lot of progress on the analytical side. Great work! Keep going.

 

[JT Smith]

I don't believe you will be able to determine the %ABV from that refractometer, at least not as easily as I suspect you are thinking it will be. If you are a winemaker you can measure the sugar content of the juice from the grapes, usually in units of Brix. From that one can infer a potential alcohol content of the finished wine. It is also possible to do a calculation to determine the alcohol content by using measurements of the juice and wine. This is because the sugar content drops in concert with an increase in ethanol. But if you just measure a random wine with a refractometer there's no way to know what the value means. Wine is not a simple ethanol-water mixture.

 

[JT Smith]

We have a number of bottles of wine that have gone off the cliff, so to speak. Usually still drinkable but some years past their prime. I use them in spaghetti sauce. I pulled one of those out and measured 250g into a large sauce pan. After 25 minutes at 60-90°C (I wasn't being especially careful) it had reduced to 108g.

I have an inexpensive optical refractometer that I purchased for $25 from amazon to make crude measurements of my espresso coffee concentration. I have tested it against a more accurate method and found it's good to about ±0.2% Brix, if I'm careful with it's use. I know how Brix relates to refractive index and I looked up some numbers for the refractive index of ethanol-water mixtures. So I figured I could use this tool to measure alcohol -- assuming it's alcohol in water alone.

Starting out, the wine measured 8.7% Brix which is an RI of about 1.3485. That in turn translates into an ABV of something in the vicinity of 30%. The label says this wine is 14.4% alcohol by volume. So obviously the other components of the wine are significant.

The reduced wine also measured 8.7% Brix. Clearly a coincidence. A decrease in alcohol should drive the RI (and apparent Brix) down and the increase in dissolved solids concentration should drive it up. They balanced!

I then added water to the 108g of reduced wine so that it again weighed 250g. That mixture measured 3.5% Brix. That corresponds to an RI of about 1.3393. If this were a pure ethanol-water mixture it would be about 12.2% ABV.

I was thinking that one might possibly infer the new ABV from the two RI readings and the ABV listed on the wine bottle. But I'm not sure how exactly. Probably I'm wasting time and old wine. It made the kitchen smell nicely though!EDIT: By the way, the old wine actually wasn't too bad. It wasn't astringent or sour and it had retained most of its character. In contrast the cooked down reconstituted wine was quite sour and otherwise pretty bland. I'm not sure what that means in terms of the chemistry, and maybe it would still be okay in certain cooked dishes. But I sure wouldn't want to drink it.

 

[ArtZ]

I don't believe you will be able to determine the %ABV from that refractometer, at least not as easily as I suspect you are thinking it will be. If you are a winemaker you can measure the sugar content of the juice from the grapes, usually in units of Brix. From that one can infer a potential alcohol content of the finished wine. It is also possible to do a calculation to determine the alcohol content by using measurements of the juice and wine. This is because the sugar content drops in concert with an increase in ethanol. But if you just measure a random wine with a refractometer there's no way to know what the value means. Wine is not a simple ethanol-water mixture.

You, you may very well right about this. The digital refractometer I purchased is intended for wine and beer making. And yes, it measures potential alcohol not absolute alcohol, ABV. The potential alcohol may not be indicative the actual ABV as you point out.

 

[ArtZ]

We have a number of bottles of wine that have gone off the cliff, so to speak. Usually still drinkable but some years past their prime. I use them in spaghetti sauce. I pulled one of those out and measured 250g into a large sauce pan. After 25 minutes at 60-90°C (I wasn't being especially careful) it had reduced to 108g.

I have an inexpensive optical refractometer that I purchased for $25 from amazon to make crude measurements of my espresso coffee concentration. I have tested it against a more accurate method and found it's good to about ±0.2% Brix, if I'm careful with it's use. I know how Brix relates to refractive index and I looked up some numbers for the refractive index of ethanol-water mixtures. So I figured I could use this tool to measure alcohol -- assuming it's alcohol in water alone.

Starting out, the wine measured 8.7% Brix which is an RI of about 1.3485. That in turn translates into an ABV of something in the vicinity of 30%. The label says this wine is 14.4% alcohol by volume. So obviously the other components of the wine are significant.

The reduced wine also measured 8.7% Brix. Clearly a coincidence. A decrease in alcohol should drive the RI (and apparent Brix) down and the increase in dissolved solids concentration should drive it up. They balanced!

I then added water to the 108g of reduced wine so that it again weighed 250g. That mixture measured 3.5% Brix. That corresponds to an RI of about 1.3393. If this were a pure ethanol-water mixture it would be about 12.2% ABV.

I was thinking that one might possibly infer the new ABV from the two RI readings and the ABV listed on the wine bottle. But I'm not sure how exactly. Probably I'm wasting time and old wine. It made the kitchen smell nicely though!EDIT: By the way, the old wine actually wasn't too bad. It wasn't astringent or sour and it had retained most of its character. In contrast the cooked down reconstituted wine was quite sour and otherwise pretty bland. I'm not sure what that means in terms of the chemistry, and maybe it would still be okay in certain cooked dishes. But I sure wouldn't want to drink it.

Some good data points for me moving forward. That's a huge discrepancy between the wine label and your refractometer measurement. Since my digital refractometer is also measuring RI, likely it won't any better in accuracy just easier to get answer with the digital display. Maybe the Brix to PA algorithm is smarter?

As a baseline, the first measurement I was going to make was to check the refractometer result against the 15% ABV stated on the bottle. So in a retry of the cal procedure, I confirmed that the unit is defective. I will return the unit on Monday and purchase a new one.

If I get agreement ( stated ABV vs. measured PA) for this initial, I'll proceed with 250mL samples using my sous vide bath. (0.1C accuracy)

Otherwise, I'll need to rethink my strategy. I did purchase a beer/winemaking hydrometer and haven't yet returned it. The downside to using this device is that it requires a 250mL sample volume. and that would be disruptive to the experiment to say the least. There are digital hydrometers but they are pricey.

Thanks for trying this experiment out; it's a big help.

 

[ArtZ]

Some good data points for me moving forward. That's a huge discrepancy between the wine label and your refractometer measurement. Since my digital refractometer is also measuring RI, likely it won't any better in accuracy just easier to get answer with the digital display. Maybe the Brix to PA algorithm is smarter?

As a baseline, the first measurement I was going to make was to check the refractometer result against the 15% ABV stated on the bottle. So in a retry of the cal procedure, I confirmed that the unit is defective. I will return the unit on Monday and purchase a new one.

If I get agreement ( stated ABV vs. measured PA) for this initial, I'll proceed with 250mL samples using my sous vide bath. (0.1C accuracy)

Otherwise, I'll need to rethink my strategy. I did purchase a beer/winemaking hydrometer and haven't yet returned it. The downside to using this device is that it requires a 250mL sample volume. and that would be disruptive to the experiment to say the least. There are digital hydrometers but they are pricey.

Thanks for trying this experiment out; it's a big help.

This site has some very small hydrometers but the site is not in English (Dutch?):
https://nl.dreamstime.com/de-hydrometer-van-alcoholmeter-een-hand-image136343314

 

[JT Smith]

Some good data points for me moving forward. That's a huge discrepancy between the wine label and your refractometer measurement. Since my digital refractometer is also measuring RI, likely it won't any better in accuracy just easier to get answer with the digital display. Maybe the Brix to PA algorithm is smarter?

Of course there's a discrepancy. Wine is not only ethanol and water.

Your refractometer "PA" will simply be the same measurement but in different units. The Brix value refers to the sucrose content by weight. Ten grams of sucrose in 100 grams of solution is 10% Brix. Grapes are actually mostly fructose and glucose but the difference in RI is not large and your refractometer may even be applying a correction. The PA reading is just another way of expressing the sugar concentration. You could probably google a formula for doing it yourself.

Each molecule of fructose or glucose can be converted into two molecules of ethanol during fermentation. So it's possible to estimate the eventual ABV by knowing the sugar concentration. Wines, even dry wines, have residual sugar, as well as other "stuff". So it's just an estimate, a "potential". The way alcohol is traditionally calculated is by measuring before and after fermentation. Even then there are some assumptions being made.

Using a hydrometer really isn't better. They are awkward because they require large samples, temperature control is harder as a result, and the good ones are glass and quite fragile. And in the end you have the same issue: how do you measure ethanol in a solution that contains other components?

One way would be with a GC. That would be the tool of choice if you had one in your kitchen. I wonder if one would fit next to your sous vide?

 

[JT Smith]

I looked at the numbers I came up with yesterday and realized I had been reading the wrong column in a table. When I did it again I got this:

8.7% Brix - original wine measurement
5.2% Brix - what a 14.2% w/w ethanol-water solution would measure

Subtract those two and you get 3.5% Brix, which is what I measured in my reduced/reconstituted wine. A naive assessment of that would be that 3.5% Brix is the residual "sugar" of the wine and all of the ethanol was gone. I'm pretty sure that isn't true so either I botched the experiment somehow or the hopeful assumption that a dealcoholized wine would refract light as if it were a sucrose solution is pretty far off.

Maybe a hydrometer would work better. But I still think using about 1/3 as much as wine in your food is the best solution.

 

[ArtZ]

Of course there's a discrepancy. Wine is not only ethanol and water.

Your refractometer "PA" will simply be the same measurement but in different units. The Brix value refers to the sucrose content by weight. Ten grams of sucrose in 100 grams of solution is 10% Brix. Grapes are actually mostly fructose and glucose but the difference in RI is not large and your refractometer may even be applying a correction. The PA reading is just another way of expressing the sugar concentration. You could probably google a formula for doing it yourself.

Each molecule of fructose or glucose can be converted into two molecules of ethanol during fermentation. So it's possible to estimate the eventual ABV by knowing the sugar concentration. Wines, even dry wines, have residual sugar, as well as other "stuff". So it's just an estimate, a "potential". The way alcohol is traditionally calculated is by measuring before and after fermentation. Even then there are some assumptions being made.

Using a hydrometer really isn't better. They are awkward because they require large samples, temperature control is harder as a result, and the good ones are glass and quite fragile. And in the end you have the same issue: how do you measure ethanol in a solution that contains other components?

One way would be with a GC. That would be the tool of choice if you had one in your kitchen. I wonder if one would fit next to your sous vide?

I ordered a replacement refractometer yesterday. And yes, my fancy unit with uP control and digital display, is still measuring residual sugar based on the Brix measurement. The fancy accoutrements may be just be putting lipstick on a pig. I still want to get a baseline with the digital refractometer at full 15% ABV and then adding water to the wine sample to dilute it to some low ABV, 3-4% and perform a retest. This is just a sensibility test.

 

[ArtZ]

Of course there's a discrepancy. Wine is not only ethanol and water.

Your refractometer "PA" will simply be the same measurement but in different units. The Brix value refers to the sucrose content by weight. Ten grams of sucrose in 100 grams of solution is 10% Brix. Grapes are actually mostly fructose and glucose but the difference in RI is not large and your refractometer may even be applying a correction. The PA reading is just another way of expressing the sugar concentration. You could probably google a formula for doing it yourself.

Each molecule of fructose or glucose can be converted into two molecules of ethanol during fermentation. So it's possible to estimate the eventual ABV by knowing the sugar concentration. Wines, even dry wines, have residual sugar, as well as other "stuff". So it's just an estimate, a "potential". The way alcohol is traditionally calculated is by measuring before and after fermentation. Even then there are some assumptions being made.

Using a hydrometer really isn't better. They are awkward because they require large samples, temperature control is harder as a result, and the good ones are glass and quite fragile. And in the end you have the same issue: how do you measure ethanol in a solution that contains other components?

One way would be with a GC. That would be the tool of choice if you had one in your kitchen. I wonder if one would fit next to your sous vide?

I ordered a replacement refractometer yesterday. And yes, my fancy unit with uP control and digital display, is still measuring residual sugar based on the Brix measurement. The fancy accoutrements may be just be putting lipstick on a pig.

I looked at the numbers I came up with yesterday and realized I had been reading the wrong column in a table. When I did it again I got this:

8.7% Brix - original wine measurement
5.2% Brix - what a 14.2% w/w ethanol-water solution would measure

Subtract those two and you get 3.5% Brix, which is what I measured in my reduced/reconstituted wine. A naive assessment of that would be that 3.5% Brix is the residual "sugar" of the wine and all of the ethanol was gone. I'm pretty sure that isn't true so either I botched the experiment somehow or the hopeful assumption that a dealcoholized wine would refract light as if it were a sucrose solution is pretty far off.

Maybe a hydrometer would work better. But I still think using about 1/3 as much as wine in your food is the best solution.

Unless I am missing the point, it sounds like your recheck was revealing that there's some hope for the refractometer. BTW, what is a GC?

 

[JT Smith]

Unless I am missing the point, it sounds like your recheck was revealing that there's some hope for the refractometer. BTW, what is a GC?

GC refers to gas chromatography. Probably more than you are willing to spend. :-)

Being human we can always hope... even if it's impossible. I'm pessimistic about using a refractometer because we don't have a formula or table for the RI of a dealcoholized wine, never mind your particular wine. Somebody smarter and more experienced could probably tell you if there were reason to hope.

I wonder if it might work better to measure the density with a hydrometer. You could heat a small sample of the wine in an oven until it is fully dry and weigh the residue. You'd need a pretty good scale. Alternatively you could heat some wine until it is so reduced that you can feel confident that very little ethanol remains. Then reconstitute that and measure the density. Either of those approaches will tell you how much dissolved material is in the wine, besides ethanol. Then I think you could subtract that off of hydrometer measurements of wine with ethanol. I think that might work. You could check it against the unadulterated wine to see if it really works out to 15%. I could just be dreaming. I'm not a scientist, I just play one in the kitchen sometimes.

 

[ArtZ]

GC refers to gas chromatography. Probably more than you are willing to spend. :-)

Being human we can always hope... even if it's impossible. I'm pessimistic about using a refractometer because we don't have a formula or table for the RI of a dealcoholized wine, never mind your particular wine. Somebody smarter and more experienced could probably tell you if there were reason to hope.

I wonder if it might work better to measure the density with a hydrometer. You could heat a small sample of the wine in an oven until it is fully dry and weigh the residue. You'd need a pretty good scale. Alternatively you could heat some wine until it is so reduced that you can feel confident that very little ethanol remains. Then reconstitute that and measure the density. Either of those approaches will tell you how much dissolved material is in the wine, besides ethanol. Then I think you could subtract that off of hydrometer measurements of wine with ethanol. I think that might work. You could check it against the unadulterated wine to see if it really works out to 15%. I could just be dreaming. I'm not a scientist, I just play one in the kitchen sometimes.

I went to the sources listed by participants in this thread, i.e., CRC etc. and was able to find density and specific heat for ethanol-water mixtures as a function of temperature but no RI. And, as you've pointed out several times, wine is not a simple ethanol-water mixture. There are some fancy hydrometers requiring only a 100uL sample volume- cost $3500.

Call me an optimist, but if the new refractometer isn't DOA, I'll try my plan to see what the PA of the undiluted wine measures in at, then dilute a sample with water multiple times and see what the meter returns for PA. In the limit, as the dilution approaches all water, the PA should approach zero. If I plot the measured PA as a function of ABV in the diluted samples, maybe we can learn something. I doubt the PA vs. ABV function will be linear, but if PA is tracking ABV closely this should be a 1-1 relation. Keep dreaming, right. Even if it's non-linear, we may be able use the non-linearity as a correction factor.

 

[JT Smith]

Call me an optimist, but if the new refractometer isn't DOA, I'll try my plan to see what the PA of the undiluted wine measures in at, then dilute a sample with water multiple times and see what the meter returns for PA. In the limit, as the dilution approaches all water, the PA should approach zero. If I plot the measured PA as a function of ABV in the diluted samples, maybe we can learn something.

PA is just another unit for sugar content. It really only makes sense in the context of unfermented juice where sugar is the main ingredient. In your wine the index of refraction differs from that of pure water not because it's a dilute syrup but because of ethanol and other components. Your refractometer is not designed for what you want it to do.

If you dilute the wine you will reduce the concentration of both the ethanol and the other dissolved solids by the same proportions. So you'll end up with a plot that describes the apparent Brix (or PA if you prefer) versus dilution level of your wine. Armed with that plot you could determine the dilution level by measuring a diluted wine. But it won't tell you that the wine started out at 15%. And if you boil off some of the ethanol it won't be able to tell you how much is left.

 

[Fra]

The alcohol-reduced wine will be used for cooking.

This is probably missing youre point, but as there may be several reasons of flavouring for using wine in cooking.

Isn't there some sort of rice vineager or balsamico hybrid, that you can use off the shelf to get a similar effect?

I have no flavour experience with chinese rice wine, but I often use balsamico vinegar or balsamico reduction in cooking. Not quite the same as wine of course, but does add some deep grape flavour and some balanced acidity in a simpler way.

/Fredrik

 

[JT Smith]

Yeah, it's not the same thing as wine...

 

[JT Smith]

I think what you really want is a plot of alcohol % of your wine versus refractometer output. I have an idea that might work to produce that, probably it won't. Maybe I will try it tomorrow. It's fun to be a little kid with a chemistry set.

 

[ArtZ]

This is probably missing youre point, but as there may be several reasons of flavouring for using wine in cooking.

Isn't there some sort of rice vineager or balsamico hybrid, that you can use off the shelf to get a similar effect?

I have no flavour experience with chinese rice wine, but I often use balsamico vinegar or balsamico reduction in cooking. Not quite the same as wine of course, but does add some deep grape flavour and some balanced acidity in a simpler way.

/Fredrik

Thanks but no. Shaoxing has a very unique flavor profile.

 

[ArtZ]

I looked at the numbers I came up with yesterday and realized I had been reading the wrong column in a table. When I did it again I got this:

8.7% Brix - original wine measurement
5.2% Brix - what a 14.2% w/w ethanol-water solution would measure

Subtract those two and you get 3.5% Brix, which is what I measured in my reduced/reconstituted wine. A naive assessment of that would be that 3.5% Brix is the residual "sugar" of the wine and all of the ethanol was gone. I'm pretty sure that isn't true so either I botched the experiment somehow or the hopeful assumption that a dealcoholized wine would refract light as if it were a sucrose solution is pretty far off.

Maybe a hydrometer would work better. But I still think using about 1/3 as much as wine in your food is the best solution.

Using about 1/3 as much wine in the recipe may be a good solution. For different recipes, the wine component can be as small as 1 tsp or as much as 2 tbs. Splitting these measures seems tedious.

 

[ArtZ]

Someone mentioned earlier of just simply reducing the ABV by adding water to a given volume of wine. With this in mind, using the simple relation C1*V1 = C2*V2 and solving for V2: V2= (C1/C2)*V1. V1 will be the starting volume. V2 will be the increased volume accounting for the added water. So for reducing from 15% ABV to 10%, with a starting volume of 250mL we get V2=(.15/.10) *.250= .375 so we'll be adding 125mL of water. This may not be radical.

If we do this again, using this time the same 250mL starting volume but now reduce the 15% ABV to 5%, we will be adding quite a bit of water. V2=(.15/.05) *.250= .750. We would need to add 500 mL to the 250 mL sample to achieve the ABV reduction. If then using this 1:1 in a recipe, seems that the flavor would be lost.

 

[JT Smith]

Someone mentioned earlier of just simply reducing the ABV by adding water to a given volume of wine....

...If we do this again, using this time the same 250mL starting volume but now reduce the 15% ABV to 5%, we will be adding quite a bit of water. V2=(.15/.05) *.250= .750. We would need to add 500 mL to the 250 mL sample to achieve the ABV reduction. If then using this 1:1 in a recipe, seems that the flavor would be lost.

Yes, it will have less flavor if you use less. You'll have to figure out the tradeoff between less unadulterated wine and more cooked down wine. Try cooking some wine and taste it.

Another thing: ethanol is a flavor component. Remove the ethanol from wine or beer and it doesn't taste the same. Ethanol is sweet. It's probably why my reduced wine tasted so sour. It was out of balance without the ethanol.

 

[JT Smith]

I did another experiment this morning. I did a few things actually.

First I measured vodka at a few different dilutions with my refractometer, just as a consistency check. The data lined up with the numbers I found on the internet.

Then I opened an old 750ml bottle of red wine (14.4%). I measured it with my refractometer: 8.4% Brix. Then I sealed some in a small jar and put it in boiling water for an hour. I wanted to see if simply heating the wine would change the refractive properties. It didn't.

At the same time I took the remaining 650ml and reduced it in a double boiler for a little over an hour, reducing it to 300ml. After cooling it I split it up into five portions, reconstituting each to the correct volume. But I didn't just use water; I also included varying measured amounts of 40% vodka. That gave me a series of samples at varying ABV. I didn't know what the values were but I knew by how much they differed. When plotted they displayed essentially the same slope as the ethanol-water (or diluted vodka) samples. And that slope is roughly 2.4% ABV/%Brix.

So I could figure out what how much my wine was reduced to. Reconstituted it was 2.3% ABV. The original reduced wine, before I added water, would have been 5.0% ABV.

Since the slope roughly matched pure (or nearly pure) ethanol-water I suspect that this is not something that will only work with the wine I chose, or even red wines in general. Probably it would work for yours as well. But I don't know that. You could always duplicate what I did this morning. Or just figure it's close enough.

The cooked wines sure didn't taste that nice though. The best of the bunch was the one I added the most vodka to. That one, which was just barely shy of the original strength of the 14.4% wine, had a sweetness the others lacked.