How to tell when fermentation is complete?

[Midnightblue69]

I've been fermenting this blackberry wine for about 2 months now. It appears to me that fermentation has been over. No evident bubles for some time and minimal sediment at last racking I added stabilizers today and would like to rack one more time and sweeten so I can get it bottled. Is there any surefire way to make sure the fermentation is stopped before sweetening?

 

[GilaMinumBeer]

A hydrometer be your guide.

 

[Midnightblue69]

How is that Gila? I must not understand SG corrctly as it pertains to this.

 

[DoctorCAD]

SG above 1.0... = still working
SG below 1.000 = probably done, but check again in a few days. If the number has not moved, its done.

 

[GilaMinumBeer]

How is that Gila? I must not understand SG corrctly as it pertains to this.

SG above 1.0... = still working
SG below 1.000 = probably done, but check again in a few days. If the number has not moved, its done.

The Dr's number 2.

Compare readings across 2 or 3 days. If the number changes between days wait another day and read again. Once the reading is teh same on both days the yeast has stalled and fermentation is hopefully complete (based on where the numbers land).

 

[drkaeppel]

Also remember to check the temperature at which your hydrometer is calibrated at (most are 60F). Like DoctorCAD said tho, if the number doesn't change over several days then it's probably done.

 

[mutedog]

If you're going to sweeten then you should add Potassium Sorbate to the wine to make sure the yeast is killed off. Just because fermentation is complete doesn't mean the yeast have all died and won't start fermenting any new sugar that you add.

 

[Midnightblue69]

Mutedog, I added PS and Campden a few days ago. I will let it set like this for about another week, rerack, sweeten and bottle.

Hoping for the best.

Thank you all!!!!!!

 

[mutedog]

Sweeten it now. Then wait a week to make sure fermentation doesn't restart. Then bottle it.

If you sweeten and bottle and fermentation restarts you will be unhappy.

 

[Jacob_Marley]

Like mutedog says, sweeten and observe.
Let it sit for a week or two in a warm environment after sweetening to see if fermentation resumes. Alternately if you (for whatever reason) want to insure the yeast are dead prior to backsweetening the whole batch, you could siphon off a small amount, give it a good shake and let it sit out to reduce the sulfite effect, sweeten it, put an airlock on and observe for a couple weeks.