What made my hard ice tea go south?

[Jason4run]

I brewed a 4-gallon batch of what was supposed to be hard iced tea. The day I bottled it I sweetened it with cane sugar and it tasted exactly like Lipton Brisk Iced Tea from the can. It was exactly what I was going for. By the next day the flavor changed quite a bit. The iced tea taste went away for the most part leaving an odd lemonade taste. It doesn't taste bad, but it doesn't taste like anything I can identify. The recipe was simple:

Steeped 4 1-gal tea bags in one gallon water
Boiled 2 quarts water with 2 cups lemon juice (from lemons) & 4 pounds cane sugar & 4 tsp nutrient.
Added to 4-gallon carboy with a gallon of water in it.
Topped off for 4 gallons with water.
Pitched Red Star Champagne yeast starter at about 70 deg F.
Fermented a bit warm at around 75 deg F. for 15 days.
Bottled it in PET soda bottles.

What would make the taste change so quickly?

 

[Yooper]

Well, sugar is fermentable. So, instead of sweetening the tea, it would ferment out. Champagne yeast should take just about anything dry. It can go up to 18% ABV. So, my guess is that it wasn't done fermenting, and you added more sugar that will ferment out.

My worry would be that you'll have bottle bombs so if you bottled in glass, you should put them somewhere safe for when they explode.

If you make another batch, you have to ferment it until it's completely finished. A hydrometer will help you know when that is. After it's finished, you can stabilize it with sorbate and campden, and then sweeten to taste. That will keep the yeast from reproducing and fermenting out the sugar.

 

[Jason4run]

I failed to give you all the info...

It was dry as a bone...0.992 two days in a row. I planned for it to be drunk right away, so I placed the soda bottles in the refrigerator. Only after they were cooled to refrigerator temps did I add sugar and only to one at a time. The original taste (the sample that tasted like Lipton) was taken straight out of the carboy, sweetened, iced and imbibed.

I siphoned it out of the carboy with the siphon tube all the way to the bottom of the bottles. I filled them up to 1" to 1/2" from the cap. Even though I did that, my guess is that oxygen got to it. I shook the bottles to mix the sugar.

I might try it again and this time try and fill the bottles with CO2 before I fill them. It was quick, cheap and the first taste I had was great. I'd love to be able to recreate that.

 

[azscoob]

I would do it again the same as before, bottle as is and cold store them, then sweeten your glass as you would regular iced tea, no need to pre-sweeten! or maybe sweeten with splenda at bottling, since its not fermentable it shouldnt change flavor wise after bottling. thats just my thoughts!

 

[Yooper]

I don't know why the flavor would turn. If it was done fermenting, it shouldn't change. That's a real puzzle to me.

I'm sorry I can't be more helpful- I have no idea at all, based on the more complete information you've given it seems like your procedure was sound.