Using UV treated water for brewing

[scottatron]

Do to many reasons, I will be using RO or perhaps nano filtered water for brewing purposes. I will also have to use a plastic cold liquor tank stored in my cold room for storing the RO water. This will be used for cooling the wort and be recaptured into my HLT for brewing.

Since I thought that the water in the CLT will sit for quite some time between brews, I thought a UV filter could be used to sterilize the water before it goes into the tank. I have never brewed in a brewery that uses a CLT before so I am not sure if this is required.

Is there any reason to not brew with water that has been exposed to UV? Is it necessary in this instance? Should I fill my CLT up with water a day before I brew to minimize time sitting in the tank?

Thanks for any suggestions

[dick murton]

I assume you are going to RO or nano filter to remove undesirable minerals, otherwise - why?

If you have RO or nano filtered your water, it will be sterile anyway, so no need to UV treat at this point. Don't forget, you almost certainly need to pass the water through a carbon filoter to remove chlorine or chlorine compounds that can damage the membrane. Check with the supplier of the equipment.

UV has absolutely no residual anti bacterial / yeast / viral effect, so any storage and distrubution system downstream of the UV steriliser has to be maintained in sterile condition itself if you want it to remain complelety sterile. However, this is not an absolute necessity. For brewing purposes, I suggest that your tank has CIP facilities, and you clean the tank a couple of times a year, just to ensure there is no build-up of bacteria / algae etc. The mains through the UV lamp and into the storage tank, and from the storage tank also need to be cleanable on a periodic basis. I suggest that for brewhouse purposes, all this kit should be cleanable, but maintenance of absolute sterility is not required.

When the cold water is passed through the wort heat exchanger, providing the temperature is above about 65 C and then stored at that temperature (normally it will be hotter), then the heat will pasteurise the water, and kill of any extant bacteria / moulds etc. Again, ideally this water pipework and the hot water tank should be cleaned periodically, especially if you add mineral salts to the hot water tank rather than the grist itself.

UV does not physically affect the water, nor have any chemical effect on the mash salts / grains etc, so no problem there. I just think it is a waste of money on your part to put in UV at this point. Absolutely sterile water is only required when it is added directly in the form of dilution water, or indirectly as additions or as CIP final rinse water residues.

[gitchegumee]

+1 for Dick's on-the-spot analysis yet again. I will add a few notes; I would NOT UV the water into the CLT--like Dick mentioned, it's already sterile and may not necessarily stay that way in a tank, so further UV is a waste. If you need sterile water for rinsing tanks, as an example, then UV the water OUT of the CLT. Put the UV power on a set of auxiliary contacts on your CLT pump so that it turns on only when you run the CLT pump. Easy. That is all--Good luck!

[dick murton]

The last response has prompted a thought.

All the UV systems I have experience of have a warm up time of a few to several minutes. So the unit will not kill bugs as soon as the power (and the pump) goes on. You will either have to introduce a suitable dealy before any valves open and the pump is energised, or will have to leave the UV lamp on, probably with a periodic reasonably high flow bleed off to prevent the lamp overheating and burning out, or less economically, with a permanent recirculation through the UV lamp. If you run water through the unwarmed UV lamp, all you will do is potentially introduce infection downstream of the UV lamp - rather defeating the purpose of it.

[scottatron]

Thanks for all the answers everyone. I appreciate the feedback. As of right now, I'm probably not going to get one.