Is UV treated apple juice effective at killing wild yeast?

[obeahsf]

We are planning to make 25 gallons of hard cider to give away as wedding gifts. The orchard we were planning to go to says that they do not pasteurize, but do apply UV filtration to the juice. I've read many conflicting things about what UV does and does not remove from the equation. I'd be happy to experiment with a smaller batch at another time, but we want to ensure a clean ferment. We also don't want to go through the process of pasteurizing on the stove in 10 batches and using wort chiller 10 times.

I'm wondering if I pitch a commercial yeast fairly quickly, if that will be enough. My understanding is that most bacterias will be killed by the UV, but that wild yeasts/brett may not be affected. I was thinking if I had a good starter, that most of the sugar would be eaten by them time wild strains started doing their thing. I guess brett, being the workhorse that it is, may start to make it's presence known after awhile in the bottle..? We will be bottle-conditioning the juice. We don't plan to back-sweeten it.

I also heard an interesting idea the other day about pasteurizing the bottles after bottle-carbing. The brewer, who primed with fresh apple juice, used this process also to retain a little RS.

Rambling, but thoughts on UV/forgoing heat for this very big batch?

Thanks!

 

[crispbrew]

I wouldn't be worried about it. UV treatment should take care of the wild yeast in the juice to a negligible amount. Just add yeast quickly after purchase or leave the juice refrigerated before you get around to it to be sure. The commercial yeast should be able to out compete the small amount of wild yeast present, preventing their characteristics from coming through.

If you think about it, if the wild yeast were at a level where they could impart flavors then you would likely see spontaneous fermentation from pure juice fairly quickly. Might be a fun experiment to try putting a gallon of juice in a carboy and seeing how long before it starts to ferment on its own.

 

[LeBreton]

UV pasteurization does not have a great effect on wild yeast in apple juice. The point is to eliminate microbes that pose a health risk to humans, such as e. coli etc, not to prevent fermentation, which is why even UV pasteurized juice can have preservatives added and is kept refrigerated.

The good news is that, as crispbrew mentioned, assuming the juice has been handled and stored properly, the wild yeast population is probably low enough that any commercial yeast you pitch will very rapidly out-compete them.

If you're anxious about wild yeast, consider adding 50ppm (typically 1 tab/gallon) sulfites the day before you pitch to give your yeast a better chance. Way less work than pasteurizing the juice at home.

 

[gratus fermentatio]

I had 1 batch of UV pasteurized sweet cider that had a problem (flowers of wine), but I could've easily avoided that if I would've sulfited the must prior to yeast pitch. I was able to save it though & it turned out ok. Now I sulfite UV pasteurized juice/cider, just to be on the safe side.
Regards, GF.

 

[obeahsf]

Thanks for the great info all! We are picking up the juice from the orchard the day they press it, with the only treatment being UV (no preservatives). No bottling, just straight into carboys at the orchard. We intend to have the yeast pitched within a 2-3 hours of picking it up, during which time it won't be refrigerated. Since we don't have room to refrigerate such a large amount, there wouldn't be time to add sulfite that far ahead of time. I assume adding the sulfite tab just before pitching also tamp down the commercial yeast?

If that's the case, do you think we should forgo?

 

[domilsean]

Just for fun, I let a gallon of UV pasteurized cider (also it had "less than 1/10 of 1% of Benzoate of Soda" added) sit near the heat vent for about 2 weeks. It fermented like mad at about the 2 week mark. I never added anything in.

That being said, I think you pitch your own yeast, they'll take over, mainly because that strain will be stronger and ferment quickly (the natural yeast takes a bit).

 

[WVMJ]

Add the sulfites as you fill up each carboy, take it home, make a starter of your yeast, 24 hrs later add your yeast, you dont need to refrigerate the sulfited juice, that is why you sulfite it to knock everything back before you add your yeast. WVMJ

 

[obeahsf]

That sounds like a great plan. Definitely appreciate all the help!

 

[obeahsf]

I have one follow up question:

If we add sulfites to the juice at the Orchard, then we decide to pitch the yeast that day, would they also make the commercial yeast ineffective? If so, we can definitely wait the 24 hours. Whichever the case, we would still get the starter going a day early. It will take about 3 hours form picking up the juice, before we are home and ready to add yeast.

Thanks!

 

[domilsean]

You should give it about 24-36 hours for the sulfites to gas off, as I understand, before pitching yeast.

 

[gratus fermentatio]

Minimum of 12 hrs, 24 is better; more than that is a waste of time.
Regards, GF.