measuring alcohol content in a finished wine??

[wine newbee]

I just tried using a hydrometer to see what the alcohol % is of my (1st) newly-bottled grape wine. The device, basically, sank! OK - I checked online, generically you might say, and the little blurb said a hydrometer can't be used for finished wine!

Is that right? Appears to be, per my experience of this morning.

Can I use a refractometer, then, for this?

Thx for any info; I haven't really looked at any literature or notes since I started all this last summer-fall, so I'm pretty rusty ....

 

[sour_grapes]

You need to know the specific gravity of the must BEFORE and AFTER fermentation. The difference in those two number reveals the alcohol content (ABV). Do you know the SG before the fermentation?

 

[Chuck E]

I just tried using a hydrometer to see what the alcohol % is of my (1st) newly-bottled grape wine. The device, basically, sank! OK - I checked online, generically you might say, and the little blurb said a hydrometer can't be used for finished wine!

Is that right? Appears to be, per my experience of this morning.

Can I use a refractometer, then, for this?

Thx for any info; I haven't really looked at any literature or notes since I started all this last summer-fall, so I'm pretty rusty ....

The hydrometer will "sink" in finished wine. You will see it measuring in the .990 range, which basically means there is no more sugar to ferment. To calculate alcohol % you need to know what your hydrometer reading was when you started the batch of wine.

 

[wine newbee]

You need to know the specific gravity of the must BEFORE and AFTER fermentation. The difference in those two number reveals the alcohol content (ABV). Do you know the SG before the fermentation?

Hi, Sour -- my SG initially was 1.08; my one for this morning was 1.02. I used a calculator online (a beer-maker's website, I think) and per it, the ABV = 8.15% and the ABW = 6.47%. Tasting the finished product, somehow it seems more "alcoholy" than 8.5, but that's just perception, so I can't trust it.

Does the calculation seem right to you guys?

 

[wine newbee]

The hydrometer will "sink" in finished wine. You will see it measuring in the .990 range, which basically means there is no more sugar to ferment. To calculate alcohol % you need to know what your hydrometer reading was when you started the batch of wine.

Obliged, Chuck; yeah, my hydrometer did do the 0.990 reading; made no sense to me, at 1st. The things ya learn ....

Mitch

PS: I hafta say, the wine really looks beautiful in the btls; I'm eager to give away some 750-ml btls to special friends (most of whom've never had home-made hooch). This is my 1st try at home-made (other than the mead I made last summer; I think it's kinda hard to screw that up; grapes -- easier to bomb with) ....

 

[sour_grapes]

Hi, Sour -- my SG initially was 1.08; my one for this morning was 1.02.

Obliged, Chuck; yeah, my hydrometer did do the 0.990 reading; made no sense to me, at 1st. The things ya learn ....

Mitch, there is quite a bit of difference between 1.020 and 0.99x. Can you clarify which is the correct figure?

 

[wine newbee]

Mitch, there is quite a bit of difference between 1.020 and 0.99x. Can you clarify which is the correct figure?

OK -- maybe I'm not using correct terminology (since I'm still pretty new), but ...

the 0.999 came from when I used a hydrometer on finished wine this a.m. I'm told that's not legit use for the hydrometer.

The 1.08 and 1.02 came from the before and after Spec Grav readings of my wine with use of a refractometer. I'm told that's the way to go.

Does this make more sense?

 

[sour_grapes]

The 1.08 and 1.02 came from the before and after Spec Grav readings of my wine with use of a refractometer. I'm told that's the way to go.

You were misinformed. You cannot (easily) use a refractometer after fermentation has commenced. The problem is that alcohol has a different index of refraction than water does, and so it skews the measurement.

If your hydrometer read 1.080 when you started, and 0.999 when you finished, your ABV would be about (1.080-0.999)*131 = 10.6% ABV.

 

[barryjo]

OK, so you don't have a beginning SG. You might try this method. Access a website called "Honneyman,alcohol". It gives a good calculation of the ABV. And since ebulliometers run over $700, I like this much better. It takes maybe 20 minutes and is simple. I like simple. Print out a copy of the conversion chart with instructions and you are good to go.

 

[wine newbee]

You were misinformed. You cannot (easily) use a refractometer after fermentation has commenced. The problem is that alcohol has a different index of refraction than water does, and so it skews the measurement.

If your hydrometer read 1.080 when you started, and 0.999 when you finished, your ABV would be about (1.080-0.999)*131 = 10.6% ABV.

Much obliged, Sour; I have to admit, the stuff tastes more like a 10.6 than and 8.5 ...

Mitch

 

[wine newbee]

OK, so you don't have a beginning SG. You might try this method. Access a website called "Honneyman,alcohol". It gives a good calculation of the ABV. And since ebulliometers run over $700, I like this much better. It takes maybe 20 minutes and is simple. I like simple. Print out a copy of the conversion chart with instructions and you are good to go.

Thx a heap, Barry -- I checked it (had never heard of it, naturally) ....

Mitch

 

[barryjo]

Thx a heap, Barry -- I checked it (had never heard of it, naturally) ....

Mitch

I would like to hear your comments about this process and the results.

 

[wine newbee]

Sure thing: it was easy to use. Per the chart, my values led to a finding of 10.5%. Sounds pretty alcoholy to me, and made more sense than the original 8.5 I had at 1st. Fairly strong stuff, and exactly what I wanted. Thx again ...

Mitch