Glycerin is a by product of fermentation. Some yeast produce more of it
than others and some conditions favor it's production and I think some
grapes tend toward it. I don't know exactly what they are but it happens.
The army, in wars past, has used fermentation to manufacture glycerin.
Anyway, glycerin is sweet and adds legs to your wine. Some people add
glycerin for the legs. When a wine comes out tasting sweet but has a low
RS, it may be that you have a high glycerin content. You might check it to
see if it has strong legs.

Ray

"Lee" > wrote in message
oups.com...
>I guess I'm late to this discussion, but I have another thought.
>
> This past fall, Ihad a batch of syrah which was doing the same things
> as your Cab mix. Ultimately, I innoculated for MLF, and then
> re-innoculated after several months. Still, I was getting persistent
> minor bubbling. Finally, after fooling with this wine for about 7-8
> months, I just tried degassing it with a stirring wand on a drill.
> After LOTS of agitation, the bubbling stopped, and hasn't
> re-startedafter another 2-3 months. It tastes "sweet", but the R.S. is
> virtually zero.
>
> So, I wonder if the sweetness is just the flavor of your grapes, and
> the bubbles are retained CO2.
>
> Lee
>