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View Full Version : backsweetening; refermenting issues?



shanek17
08-27-2012, 09:45 PM
So I have succesfully done my first backsweetning...well almost succesfully.

So i made a 5 gal 11% welchs frozen grape wine and it fermented to an SG of .992. I also added 1/4 tsp of sulfites and then moved it to the basement for 1 month of bulk aging.

Then on august 22nd (which is 6 days ago from today) I added 2 cans of welchs frozen juice to the welchs 11% alcohol wine. I also added 4g of sorbate and 1/8 tea spoon of sulfites to help out. The sorbate and sulfites were purchased within the last 6 months from the LHBS. Now today on august 27th i brought the carboy from the basement which is 64F and brought it upstairs to a 75F room. I looked at the head space and noticed there wasnt very much, possibly because the liquid was getting warmer and expanding, but the actual head space was very minimal at 1/4 of an inch! I then opened up the solid rubber bung and it made a LOUD pop sound and made me jump pretty good! and I watched a bunch of bubbles continue to rise up for a little bit.

So what the heck is going on here? Is it refermenting in the carboy? or could this be a build up of pressure due to the little amount of head space and perhaps some co2 left in the wine. I also tested the co2 level in the wine by shaking a small amount in a jar and when i took the lid off it made a small pop sound and I did notice bubbles coming up. The weird thing is I degassed this wine upstairs at 75F for weeks and could have sworn I had it degassed plenty. I even racked it a couple times before putting it in the basement to help release co2.

Chevette Girl
08-27-2012, 10:03 PM
Hehe, fun with wine kits, doing this with white wine and Welch's Raspberry is awesome.

A couple possibilities. Every time I have stabilized a wine, it made bubbles for a couple of hours. So it could be that, especially if you plugged it up right away.

Also, cold water holds more dissolved gas than warm, so it could be forcing it to degas as it warms up.

Trust your hydrometer. If the SG isn't dropping, you're fine, it's just got gas :)

shanek17
08-27-2012, 10:43 PM
Hehe, fun with wine kits, doing this with white wine and Welch's Raspberry is awesome.

A couple possibilities. Every time I have stabilized a wine, it made bubbles for a couple of hours. So it could be that, especially if you plugged it up right away.

Also, cold water holds more dissolved gas than warm, so it could be forcing it to degas as it warms up.

Trust your hydrometer. If the SG isn't dropping, you're fine, it's just got gas :)

Interesting..thats makes alot of sense. i sweetened it plugged it up quickly and put it in cold basement. And when it was brought upstairs it sat in a warm room for half the day and warmed up to 70F. .then i opened it and heard the big bang. So its probably goo it wasnt left in a warm room to bulk age or that rubber bung probably woulda exploded off. or do you think the carboy would even explode? Has that happened to any one?

shanek17
08-28-2012, 01:40 AM
Hehe, fun with wine kits, doing this with white wine and Welch's Raspberry is awesome.

A couple possibilities. Every time I have stabilized a wine, it made bubbles for a couple of hours. So it could be that, especially if you plugged it up right away.

Also, cold water holds more dissolved gas than warm, so it could be forcing it to degas as it warms up.

Trust your hydrometer. If the SG isn't dropping, you're fine, it's just got gas :)

Just to clarify though, why would backsweetining cause bubbles or co2 pressure in the carboy? like im just hoping there hope there not fermentation Bubbles!

shanek17
08-28-2012, 01:48 PM
Deezil had a good reply regarding this topic, i thought id share it here, as it may be helpful to others and perhaps can lend more insights to getting my problem resolved.


Deezil
Moderator


Honestly, i'd bet its both residual co2 from fermentation, and co2 from refermentation.

Theres a chance you may have backsweetened backwards (sugars before sorbate?) - if not, im pretty sure you backsweetened 'too soon'

By 'too soon', i mean, too soon after adding your k-meta and sorbate.. Personally, i wait a week after adding my sorbate & k-meta before i add the backsweetening sugars (some people wait a day, some people do it immediately after dosing out the chemicals, i do it how i do because it works for me) but the important part is to give the sorbate time to bind with the yeast present & keep them from budding/multiplying more..

If you want to add the sugars sooner rather than later, stir more (but dont oxidize, which is why i wait) to get the sorbate mixed around..

I think the sorbate didnt have enough time to find all the yeast so the yeast seen the sugars and kept eating until the sorbate found them.. Check your SG - is it the same that you backsweetened to? That'll tell ya



yea i think your rite, some residual co2 and refermentation. I actually added sorbate and k meta to it and then did sugar additions, but i probably only waited 5 minutes before pouring in the sugar. I dont remember if I stirred the sorbate and kmeta once it was in there, but I think i did. But what confuses me here is this. if the sorbate takes time to bind to the yeast to keep them from multipying then why is the sorbate not working yet? its been 1 week since i added the sorbate so that should be enough time for them to work rite?

and just an update on the wine, after i pulled the bung off and heard the loud pop I put the solid bung rite back on there and then roughly half a day later I pulled the bung off and was suprised to hear that loud pop again! And when im looking inside the neck of the carboy there are alot of visible bubbles riseing up , so i think its safe to say its refermenting again....Its under an airlock now but where do i go from here?

I enjoyed the slightly sweet taste that the back sweetening did for this wine, but now it looks like the yeast are going strong and going to eat up all the sugar, leaving me with a dry wine again. (also I used a high tolerance yeast, possiblly the 1116 or 1118 ) I guess maybe ill have to do another back sweetening.

oh and about the hydrometer... I was so focused on doing the back sweetening good that i totally forgot about the hydrometer, so thats a mystery now. oh well I took a hydrometer reading now and its at 1.000, initially the OG was .992, so ill keep an eye on it and see if it will ferment to dry.

Chevette Girl
08-29-2012, 11:51 AM
<shrug> I get airlock activity when I add sulphites and sorbate, whether I backsweeten at the time or not. I suspect it's because the k-meta ultimately produces SO2 gas, or possibly provides nucleation sites for degassing if the wine wasn't thoroughly degassed.

And you'll see from a few threads around here that even with sorbates, fermentation can continue. It's the sulphites that knock out the yeast.

Just keep an eye on your SG, if it changes, it's not safe to bottle and you'll either want to wait until it stops, or hit it with half a dose of k-meta. If there's still airlock activity, you might want to degas it a few times too, see if you can make that go away.