When to call a stuck fermentation?

[Paulie vino]

I started a cherry wine from 2 lb. Of fresh cherries from my tree. And four 32 oz. Bottles of store-bought cherry juice without preservative. It fermented for about 4 days and the SG was getting low so I put I under airlock days and then it stopped at 1.002. I ran into some hydrogen sulfur smell prior to this which was address by adding more fermaid o. The SG has stayed steady for about 4 days now. I stirred it today and we'll see if it restarts. Any suggestions? Should I take off the airlock?
My notes are below. Any help would be appreciated. Thanks



2 lbs of montemorcy cherries from my tree and upstate tree.
32 oz bottle of Lakewood pure tart cherry not from concentrate
3x 32 oz bottle Knudsen tart cherry from concentrate
0.9 g lallzyme ex
No extra water added
1.25 g go ferm protect
1.1 gram moncharet yeast

6/16- de stemmed all cherries and crushed by hand in pot. Started to pull pits but that was too time consuming so I stopped and left most in. Wanted to use only cherries but didn't have enough so I added juice from store. Added 0.9 g lallzyme ex and will wait a few hours to add yeast

220g sugar added in and stirred and another 234g.

Starting sg before sugar 1.052. after sugar 1.090. ferm calc seems to be accurate

Used 1/4 cup hot tap water at 98 degrees to make yeast starter (1.25 g go ferm and 1.1 g yeast)

915pm pitched yeast. Covered pot with kitchen towel

6/17- 645am sg 1.086. added 0.7g of fermaid O (will add other 0.7g at 1/3 sugar depletion around 14 brix or 1.059 sg).

6/18- 830am very foamy, smells a little like rotten eggs, swamp gas. Sg 1.054. stirred very well which helped with the smell a little. Added 0.9g of fermaid k and stirred in again. Smell was better but still present.

830 pm- still smells like sulfur. Splash racked by pouring into 6 galllon bucket and back into pot 4 times. added0.42g fermaid O stirred well. Smell was better after, will check tomorrow morning. Sg was around 1.046 ( hard to see because of foam in cylinder)

6/19- 730 pm sg 1.006

6/20- 945pm sg 1.002. Smells better. Tastes good, tart and yeasty

6/21- racked by pouring into 1 gallon carboy with white stopper and airlock, extra was racked into small wine bottle and stopped with vacuum seal pump top for temporary storage. SG 1.002

6/24- SG 1.002 still, foam residue on top of wine like it's still fermenting but SG hasn't changed.

6/26- SG unchanged. Stirred wine to see if it restarts

 

[Rice_Guy]

* yes you are probably finished/ AKA stuck. 1.002 is not a bad place to be. Commercial wine will do processes to stop the fermentation at 1.005 or even 1.010 since this results in more fresh fruit flavor.
* Sulfur/ H2S smell is a concern. It sounds as if you took care of it,, GOOD! Sulfur is detectable at ppb levels where as fruity aromatics are detected at ppm levels. If H2S stays at detectable levels it reacts further into mercaptans which have a fried chicken/ meaty taste. In the future consider higher levels of YAN. In the future if you are doing whites they are more prone to develop mercaptan flavors.
* Oxygen is the enemy of alcohol. I would not try to restart a 1.002 fermentation for the goal of producing 0.25% additional alcohol. The added oxygen will create off flavors. Once I am below 1.030 gravity I try to minimize oxygen as adding extra K meta bisulphite, and keeping under airlock.

 

[Paulie vino]

Thanks for the advice. My plan is to leave the wine as is under airlock for the next week and a half (I will be out of town). When I come back I will rack off the sediment and see if the SG has changed. If it's still the same do I need to add potassium sorbate at bottling to be on the safe side?

 

[ChuckD]

Thanks for the advice. My plan is to leave the wine as is under airlock for the next week and a half (I will be out of town). When I come back I will rack off the sediment and see if the SG has changed. If it's still the same do I need to add potassium sorbate at bottling to be on the safe side?

After racking off the sediment I would put it back in a carboy, add k-meta, and let it age for a few more months. It undoubtedly needs to clear yet. After that, if the FG hasn’t hanged you should be good to bottle. Unless you back sweeten. Then definitely add sorbate.

 

[Rice_Guy]

. If it's still the same do I need to add potassium sorbate at bottling to be on the safe side?

My assumption is that under nine months age one will normally have some live yeast in a wine. With nine month/ bottle for contest I have had refermentation five times in 22 years. Suspended yeast aren’t really visible,,, but they will get
you.