sulphur and sour cider oh my

[emart]

greetings cider brewers.

I just bought about 5 gallons of cider to brew last week and used montrachet yeast. the other day it just started spewing sulphur like crazy. the yeast also just bubbled away so hard it flowed into my airlock 3 times. 2 days later thankfully the sulphur has finally gone away (you could smell it all the way from my basement to my kitchen upstairs) and now it has gone from being tangy and semi sweet is extraordinarily sour. I have never had a batch go sour this fast before

is this a sign of infection or is it just a characteristic of the yeast?

and if so can it be saved?

 

[emart]

i should add that i have not added in any additional sugar and i used cider that was specifically made just for brewing. when i bought it the stuff was thick enough to float a sneaker and it was sold in 5 gallon un-refrigerated sealed buckets

 

[Pickled_Pepper]

Some yeasts produce more of that smell than other's I've heard. I've never used the montrachet yeast before so I can't say it's prone to it.

Since I started making ciders, I've always added a cup of chopped raisins to some Apple Juice on the stove and steeped or boiled them to make a "Raisin Nutrient Tea". I'm not sure if it works 100% or not, but I've never had super bad sulfur smells before. Mine usually gets stinky for a day early on, and then it's gone. (using ale yeasts)

I've also heard of people using Yeast Nutrient from the local brew store to help cut down on the odor. It apparently helps the yeast stay more healthy and they don't have to work as hard.

It doesn't sound like an infection, it sounds like your yeast fermented the cider out "dry". 1.000 FG or even lower. Wine yeasts will do that. Aging it should smooth out the sour part and the apple flavor should come back.