Anyone have advice on life of caustic used in a semi automatic keg washer? We just got a new washer and are revisiting the topic.
Background: We're mixing about 50 gallons of 2% caustic that runs for 30 second cycle x 4 kegs on the new washer. Our old rule was 60 washes from 20 gallons of a 2% caustic solution before needing to dump it. As far as anyone knows, that number came from an old brewmaster and no one knows the basis for it.
Chemical supplier says basically if the solution is cloudy you've gone too far, but we'll really need to pull stems and do a bunch of ATP testing to figure out where the bottom end of efficacy is. We are also measuring conductivity of the caustic, but I can't find anything to help establish a minimum value, again other than pulling a bunch of stems and swabbing.
Washer manufacturer says they won't give any advice on chemical use, but they have clients (of unknown volume) who only dump their chems weekly or less often.
Obviously for now we're running on the conservative end and doing ATP swabs regularly, but would like to have a little more science to establish new procedures.
I'd like to find some literature on the topic of it exists, but would be glad to hear your rules of thumb for discussion.
I am also interested to hear folk's feedback on this (not trying to hijack the thread!).
We primarily use Birko's UltraNiter acid wash + their X-puma detergent as our keg cleaning solution. However, we like to rotate in periods of caustic washings to change up the approach and help eliminate the bit of silica sediment we see in our kegs using the acid detergent. Birko recommends keeping the pH of their caustic up near or above 12pH, but even with an extended compressed air purge to evac CO2 prior to the wash cycle we see this drop to 10 or below after a couple dozen kegs. This all seems like a big pain to keep dumping chemical into the tanks for the relatively few number of kegs that can be washed. Are we just spoiled with the number of cycles we can effectively run with an acid cleaner and that's just the way it is with caustic?
I've always used titration in conjunction with chemical supplier's efficacy recommendations. Simple and effective. I would not use ATP as that approach will not show soil in caustic washing, nor beerstone with acid washing--the primary goals of keg washing. ATP seems more useful after sanitizer rinse. And certainly never use a time-based protocol (weekly) as it does not correlate with soil loading of the detergent. Number of kegs cleaned would be much more useful. If your chemical supplier cannot give you an efficacy test, then get a new chemical supplier.