Did my juice start it's own ferment?

[SteveH]

I bought some Catawba and Vidal juice from a local winery, it was very cold when i got it Friday afternoon. I set it in the shade on our deck (mid 40's temp) and brought it in after dark. We decided to put it in the bath tub (all in gallon jugs) to let it warm up to room temp before working with it. Late Saturday morning it was still cool so we moved them into the kitchen where it was warmer and decided we'd wait until Sunday morning to start the fermenting.
The Catawba reading (from the winery) was 18 Brix.
They gave me a chart for how much sugar to add to bring the brix up to 21, it was spot on for the Vidal. I didn't do my own SG reading prior to adding sugar on either. I trusted their numbers. I added the recommended 1 cup of sugar per gallon (1.5 gal) on the Catawba and took a reading, it was 18 brix... Hmmm, how could that be it was supposed to be 18 before I added the sugar. So confused, I added another 1.5 cups of sugar and now my reading was 22 brix.
I'm guessing it started it's own ferment. Now what I'm wondering, is how do I know what the ABV will be? I'm fermenting to dry and then back sweetening.

 

[salcoco]

1 cup sugar will raise 1 gallon's specific gravity 1 brix. I believe Google will have a brix/ specific gravity table comparison and you can back track what the original brix of the wine was.

 

[SteveH]

I guess I'm still confused. My mistake was not to take my own initial SG reading.
I ended up adding 3 cups of sugar (1.5 gallon batch) to get the SG reading to 1.094.
The juice was supposed to be 18 brix (1.075 SG) but i didn't confirm that.
I added their recommended 1.5 cups of sugar and took an SG reading.
That SG reading was then 1.075 (18 brix) that's what's confusing me.
(this is where I'm wondering where the sugar went that was supposed to be in the juice assuming their brix reading was correct. The only way it could disappear would be to ferment? or their readings were inaccurate?)
I then added another 1.5 cups of sugar and then my SG reading was 1.094
I then proceeded as normal.
Maybe everything is fine and I'm just a confused babbling idiot

 

[Johnd]

I guess I'm still confused. My mistake was not to take my own initial SG reading.
I ended up adding 3 cups of sugar (1.5 gallon batch) to get the SG reading to 1.094.
The juice was supposed to be 18 brix (1.075 SG) but i didn't confirm that.
I added their recommended 1.5 cups of sugar and took an SG reading.
That SG reading was then 1.075 (18 brix) that's what's confusing me.
(this is where I'm wondering where the sugar went that was supposed to be in the juice assuming their brix reading was correct. The only way it could disappear would be to ferment? or their readings were inaccurate?)
I then added another 1.5 cups of sugar and then my SG reading was 1.094
I then proceeded as normal.
Maybe everything is fine and I'm just a confused babbling idiot

Many times, when you buy buckets of juice and must, you are furnished with numbers that aren't accurate, not because anyone is deceiving the buyer, but the product varies across the vineyard. It's just not practical for the seller to test every bucket. Best bet is to take a reading when you get it. Was the juice already fermenting when you got it? If it was, it should have been evident. If it wasn't, then the numbers were just off, and your additions have gotten you where you wanted to be.

 

[JohnT]

A couple of questions...

Was the juice from a large vat that they have tested or was it from grapes that they pressed for you? If the latter, then they may have had grapes that were lighter in sugar.

Have you calibrated your hydrometer? This could also (slightly) change your readings.

It is also possible that the juice was partially fermented. I have seen this when others are using bucket juice.

How sure are you on the exact volume you have? Is it possible that you are dealing with more juice then you think?

Also, you should actually be going by weight of sugar and not volume. Weight is far more accurate. 1.5 ounces of sugar should raise 1 gallon by 1 brix.

 

[Floandgary]

Regardless of Brix/SG, the reason juices are refrigerated is to forestall any attempts at fermentation by stray/wild/natural yeasts. Some have adapted and can start at seemingly low temps, so when you start to warm, they can be going strong! I've gotten non pre-inoculated juice buckets showing signs of fermentation right out of the cooler. Since you are planning to ferment-to-dry, I would submit that there will be a sufficient alcohol content necessary to do what it is there to do!! You can always add something later if you're looking for a kick...

 

[SteveH]

A couple of questions...

Was the juice from a large vat that they have tested or was it from grapes that they pressed for you? If the latter, then they may have had grapes that were lighter in sugar.

Have you calibrated your hydrometer? This could also (slightly) change your readings.

It is also possible that the juice was partially fermented. I have seen this when others are using bucket juice.

How sure are you on the exact volume you have? Is it possible that you are dealing with more juice then you think?

Also, you should actually be going by weight of sugar and not volume. Weight is far more accurate. 1.5 ounces of sugar should raise 1 gallon by 1 brix.

The juice was from a bulk tank. I haven't calibrated my hydrometer, but I have two so at least I can compare the two next time. They filled their containers, a 1 gallon plastic jug and a half gallon plastic jug. We just bought a scale for weighing sugar and we'll start using it (their chart did have lbs, oz, cups).

They had filled the jugs to the very top, I knew I wanted to let it warm up but was afraid it would expand and leak out, which is why we put them in the tub first. The jugs just swelled instead, no leaks. I also didn't expect to have it sit a day and a half, but it did. The reading could have been off, the other juice I got from them was spot on. That's why I over thought this and panicked. If it did start to ferment I'm not sure how to figure the ABV. Suppose I could assume their numbers were right and then do the math with the sugar I added to get an idea. Thanks for the input.

 

[SteveH]

Regardless of Brix/SG, the reason juices are refrigerated is to forestall any attempts at fermentation by stray/wild/natural yeasts. Some have adapted and can start at seemingly low temps, so when you start to warm, they can be going strong! I've gotten non pre-inoculated juice buckets showing signs of fermentation right out of the cooler. Since you are planning to ferment-to-dry, I would submit that there will be a sufficient alcohol content necessary to do what it is there to do!! You can always add something later if you're looking for a kick...

Thanks for the input, I'm kind of thinking that might be what happened. Of course I didn't look for any signs of ferment. It only entered my mind when I took the SG reading after adding "the right amount of sugar" according to their number. We like the 11%-ish wine. I guess time will tell.

 

[drainsurgeon]

If you like your wine in the 11% range, you brought your SG up too high. 1.094, if it drops to .990 is going to put you in the 13.6% range. You should have left it at 1.074 which would put you right at 11% if it goes to .990. Also, it is really easy to calibrate your hydrometer. Just fill your hydrometer tube with distilled water and it should be right at 1.0. Mine reads .998 with distilled water so I am .002 lower than actual readings. Can you still add some juice to bring your SG back down a bit?

 

[Stressbaby]

...it is really easy to calibrate your hydrometer. Just fill your hydrometer tube with distilled water and it should be right at 1.0. Mine reads .998 with distilled water so I am .002 lower than actual readings.

Each hydrometer has a calibration temp. Usually 60F or 68F. Make sure your water is at the temp noted on your hydrometer when calibrating or it could be off by a little bit.

 

[SteveH]

Can you still add some juice to bring your SG back down a bit?

I don't have anymore of that juice and it's already fermented to dry. I can back sweeten with a different juice I guess which would help dilute it a bit. Thing is, I'm not sure of the alcohol content. I've searched this forum on how to test alcohol content, but it always comes back to initial SG before ferment which is an unknown to me. I guess there are two possibilities:
A. There numbers on the juice were correct and it started to ferment and I added too much sugar not realizing this and it will have a high ABV.
B. There numbers are off and my readings pre ferment show the approx. ABV

 

[Floandgary]

I don't have anymore of that juice and it's already fermented to dry. I can back sweeten with a different juice I guess which would help dilute it a bit. Thing is, I'm not sure of the alcohol content. I've searched this forum on how to test alcohol content, but it always comes back to initial SG before ferment which is an unknown to me. I guess there are two possibilities:
A. There numbers on the juice were correct and it started to ferment and I added too much sugar not realizing this and it will have a high ABV.
B. There numbers are off and my readings pre ferment show the approx. ABV

http://www.hambletonbard.com/how-to...ol/wine-alcohol-meter-homebrew-vinometer.html. A handy little device for situations just like yours!!

 

[drainsurgeon]

Each hydrometer has a calibration temp. Usually 60F or 68F. Make sure your water is at the temp noted on your hydrometer when calibrating or it could be off by a little bit.

Thanks for adding that Stressbaby. You are more than correct!

 

[Radek]

Do not risk

Do not risk to ferment Your juice on wild yeast (never know what will start fermentation) just add some wine yeast (burgund, tokay bordeaux, champagne, portwine, Sauternes, Shery, steinberg.