UV light/Cold Pasteurization???

[liquidavalon]

Just wondering if anyone has experience with UV light pasteurization or 'cold' pasteurization as it is called, with their cider?

I purchase my base fresh pressed apple cider for making hard cider at an orchard/organic market and they cold pasteurize it via UV light. The research that I have done does show that it kills all the nasty buggers in the cider and doesn't effect yeast or the stability of the cider before, during and after fermentation...but the Internet information is thin at best.

I received as a gift a hand held UV wand and wanted to use it for pasteurizing my cider. Just unsure if I use it before fermentation (even though they did it) or after...or both. Any views or opinions on this form of pasteurization would be greatly appreciated. Thank you.

 

[Daze]

personally I don't think it is going to be very effective. Commercial pasteurization techniques bombard the entire product with more than is need to insure complete pasteurization of the entire product all at once. a wand on the other hand is only going to pasteurize part of the liquid and there is no way to to completely pasteurize the entire solution if there is always part of the liquid that is not being exposed. Also it is my understanding (please correct me if I am wrong) that yeast are not adversely effected by UV light and in most cases pasteurization in the bottles is done to kill the yeast so that you can have a sweet cider.

 

[NateG]

Let me guess the cider was from EZ Orchards I just bottled 3 gallons of cider made from the same cider, just a batch from a month ago though. Worked very well, if you add sugar like I did, 1 cup brown sugar per gallon, it comes out quite strong, I got 10.8% using US-05 Ale yeast.

 

[bwittman]

The juice we used is Flash/UV pasteurized at the mill we get it from. We inoculated but also left one gallon alone and just put an airlock on it. The un-inoculated stuff kicked over just fine but took a bit longer than the commercial yeast. So experience would say that while it kills the nasty stuff, it leaves the yeast untouched. I would love to try a whole 10 gallon run with native yeast but it's a lot to dump down the drain if the native yeast isn't so great...

 

[phaem]

I have just a wiff of experience with UV pasteurization, probably short of what it takes to become dangerous. I spend my days in a lab nurturing some bugs and killing others; sometimes a person can learn a thing or two under those conditions. A hand-held UV source won't go very far on liquids but can be pretty effective on smooth solid surfaces. The commercial units use a quartz sleeve inside a polished stainless steel chamber to pass liquid through intense UV light, 1000 watts is a common size for moderate flow rates. In this way they can control the path length the UV must pass through and the time of UV exposure. Turbid liquids won't work well, but water isn't the best for transmitting UV light either, so a short path length is important. No dropping a UV source into a carboy, and no shining UV through the ordinary glass sides of a carboy. (But only an insane person would try either, so perhaps they are only foolish in theory.) The time in the chamber and intensity of UV correlates with % kill, slower flow will get better kill. Yeast is definately affected by the UV, but typical pasteurization conditions are not sterilizing and therefore some live yeast are likely to remain (along with some of the other bad bugs). The UV light acts on the DNA (and RNA if we must get more technical) in the cells, damaging it. Enough damage and copies cannot be made, yielding replication failure and ultimately death. Moderate damage just takes some time to repair before the bug is back in business.

If you're adventurous and haven't done so before, look up 'Cobalt 60' and ponder what that could do for cider (and the careless user).

 

[liquidavalon]

Let me guess the cider was from EZ Orchards I just bottled 3 gallons of cider made from the same cider, just a batch from a month ago though. Worked very well, if you add sugar like I did, 1 cup brown sugar per gallon, it comes out quite strong, I got 10.8% using US-05 Ale yeast.

Yes...EZ Orchards is the BEST place in Salem to get "olde school" cider to use. I just started a new batch tonight infact...just a one gallon tester batch. I am using for the first time, Lallemand Nottingham Ale yeast...I have heard that it is a good yeast for semi-dry to sweet ciders ( kinda aiming for Woodchuck Amber taste ).

 

[liquidavalon]

A hand-held UV source won't go very far on liquids but can be pretty effective on smooth solid surfaces.

So would you think that it would be effecient for a final pass in sanitizing my equipment before use?? I understand that NOTHING takes the place of propper sanitation cleaning procedures, but would it help?

BTW: I have a Spectroline MiniMAX UV-5G, 5-watt, Short wave 254nm wand that I am using ( my folks got it for me because I am taking sterile processing technician classes and I wanted something that I could use at home. ) Much smaller than a 1000 watt unit = )

 

[ajbram]

I posted this in a similar thread before... the hand wands they sell are even less powerful than the aquarium sterilizers

I have worked extensively with UV sterilizers in water quality applications. Typically the bank of bulbs takes up an entire room (they're the size of 4ft. fluorescent bulbs and to get the kind of output you need to achieve sterilization you need lots of them). Water is trickled over the bulbs at low flow rates and very shallow depths (and that's for water that is already gin-clear). The aquarium sterilizer that you posted is designed to control algae populations by overloading their photosynthetic apparatus with UV light. This basically keeps the algae from being able to photosynthesize. They die as a result of not being able to produce the cellular products they need. The UV intensity of this piece of equipment is not sufficient to kill microbes (including yeast) outright. Like someone mentioned earlier, you would need a seriously badass setup to achieve what you have in mind. That equipment is not commercially available and it costs tens of thousands of $.

 

[aNYbrewery]

Yes...EZ Orchards is the BEST place in Salem to get "olde school" cider to use. I just started a new batch tonight infact...just a one gallon tester batch. I am using for the first time, Lallemand Nottingham Ale yeast...I have heard that it is a good yeast for semi-dry to sweet ciders ( kinda aiming for Woodchuck Amber taste ).

How much do you pay per gallon to buy from the source if you don't mind me asking?

 

[liquidavalon]

I think it is between $6 and $8 a gallon at the orchard...but that is the premium stuff straight from the organic orchard.

 

[phaem]

So would you think that it would be effecient for a final pass in sanitizing my equipment before use?? I understand that NOTHING takes the place of propper sanitation cleaning procedures, but would it help?

BTW: I have a Spectroline MiniMAX UV-5G, 5-watt, Short wave 254nm wand that I am using ( my folks got it for me because I am taking sterile processing technician classes and I wanted something that I could use at home. ) Much smaller than a 1000 watt unit = )

For smooth surfaces where you are not penetrating glass, plastic, or into crevices, yes - that handheld unit I think will be effective with under 60 seconds of exposure held a foot or less away. This is some guesswork on my part not being familiar with the output specs of the product. I'm assuming an output of around 1 watt if the bulb is warm and decent reflective surfaces behind the bulb. Carboys, wine thiefs, tubing, and things like that will present (insurmountable) problems I think due to poor UV penetration. That is my take, for what it is worth. This wavelength of light is not particularly freindly to human surfaces, you probably know, so some care is warranted.