Problem with my cider experiment need help?

I tried a twist on applewein by adding apple-strawberry-kiwi concentrate to my applejuice with two pounds of brown sugar. I made this applewein with red star montrachet yeast about a week ago. It is a four gallon batch which includes four jugs of applejuice and three cans of strawberry-kiwi concentrate. I also put in four tablespoons of yeast nutrient. My problem is when I am looking at my bucket nothing is happening anymore like there is no air coming out of the airlock. Is the yeast finished and is there anything I can do to get the yeast going again?

What was the OG what is the current SG. 4 TABLESPOONS is a lot of nutrient. Id have used 4 teaspoons. It is probably close to done. If so let it rest at least two more weeks.

This strawberry kiwi concentrate - where did you get it? What was the ingredients list?

Welches makes a strawberry-kiwi concentrate

I'm going to bet the concentrate has sodium benzoate in it.

I used welch's concentrate but I cant remember what they ingredients were. I know it said 100% Juice on the can and I didn't see any negative ingredients on the can should I just let it sit for a couple more weeks and bottle it and if I do should I add potassium sorbate to kill the yeast indefinitly?

Hydrometer use is key in brewing anything, so I suggest picking one up asap, they're only about 8 bucks. That being said, the only way to know if your stuff is done is to take a hydro reading. Airlock activity should never be used as an indicator of fermentation, that can lead to some dangerous bottle grenades once you bottle.

I've used welches concentrates before, and never had a problem, so you're probably fine there. The amount of sugar you had in there to begin with was probably fairly high, but montrachet yeast can cut through it fast, particularly with the nutrient you added, and if it was at room temp. If it looks fairly clear, and there's a good compacted layer of sediment on the bottom, I would rack this to a secondary and take a gravity reading. When you gravity hasn't changed for about a week, then you're done fermenting.

Welches dosen't have sorbate or benzote in it. That shouldn't be the problem. Mike is right get a hydrometer and check the readings. Is your air lock or cover on tight?

I'm with Lapaglia & MikeRLynch on this one... It might be done, apple juice, even with concentrate added can ferment pretty quickly with the right yeast. The ONLY way to be certain though, is to use a hydrometer; they're cheap, easy & available at any homebrew store. Regards, GF.