Sanitizing Fermenters

[claponsie]

Hey guys,

I have quick question regarding acid-based sanitizing solutions. I currently mix with hot water at the manufacturer specified ratio and verify with a pH meter. I always CIP sanitize immediately prior to filling the fermenter, but in an effort to make my solution go further, I wondered if a fermenter could be sanitized in advance? I'm interested in hearing if any of you store your solution, and in what type of vessel, and how you determine when it is no longer effective. I'm also curious if anybody sanitizes their fermenters several days in advance before filling. Logic tells me that if it is sanitized when it is closed and sealed, then the only contaminates would the bacteria that survived the acid cycle and/or airborne bacteria still present in the fermenter. I didn't want to test the idea and potentially ruin a batch. Thanks!

[BDL]

I've worked places where we sanitized as much as 5 days in advance and never had any troubles. we pressurized the tank while cycling the sanitizer. Then drained the sani out, and as long as the tank stays pressurized we weren't concerned about it. clean and sanitized tank, plus positive pressure stands to reason the tank should stay in a stable state pretty much indefinitely. If the tank is clean there is no food for anything to grow, and if its pressurized microbes have no way to enter the tank.

I've heard a lot of mixed opinions on reusing sanitizer. My opinion is it isn't very expensive, I would use fresh everytime, if it fails to properly sanitize because its reused even one time, the cost of a lost batch far outways the cost of extra sani. It's cheap insurance.

[beerguy1]

BDL took the words right out of my mouth so I will not repeat what he said. I have been doing this exact thing for 14 years now with out a problem. .You will find those that disagree but sometimes with as busy as I am I just have to do things ahead of time to try and get beer out the door

[soia1138]

Empty tanks don't make money. Seems like a lot of wasted time to stretch a few gallons of sanitizer. Why would you need to sanitize the tank ahead of time in order to reuse the solution? I get more use out of my sani solution by using it for my HX. Once the sani CIP is complete on the tank (while the brew is underway), the solution is pumped out from the tank through the HX. The HX is closed off before the entire tank is empty leaving the entire loop packed until the KO. Sure you could sanitize ahead of time in theory but why would you, there is no advantage, you are only leaving opportunity for things to go wrong. Slight as it may be, its still there.

[GlacierBrewing]

I echo BDL. I pre-sanitized my tanks nine times out of ten. Sometimes as long as a week or two prior to filling them. If your cleaning/sani protocol are sound, your tanks should remain ready for product for quite awhile. I've used this technique since 1993 with great success.
Prost!
Dave

[claponsie]

Empty tanks don't make money. Seems like a lot of wasted time to stretch a few gallons of sanitizer. Why would you need to sanitize the tank ahead of time in order to reuse the solution? I get more use out of my sani solution by using it for my HX. Once the sani CIP is complete on the tank (while the brew is underway), the solution is pumped out from the tank through the HX. The HX is closed off before the entire tank is empty leaving the entire loop packed until the KO. Sure you could sanitize ahead of time in theory but why would you, there is no advantage, you are only leaving opportunity for things to go wrong. Slight as it may be, its still there.

Interesting point. I agree, in theory. In a world where everything goes perfectly, I would never have an empty tank. Being the only brewer and having responsibilities that stretch well beyond what the average brewer is responsible for, I sometimes have an empty tank =). Our fermenters are 3x larger than our brew system, which means that I am constantly brewing, and sometimes the cold-side process goes faster than how quickly I can fill the tanks.

Thanks for the input, everyone.

[mmussen]

The 2 breweries I've worked at that did this had strict time limits that a tank was considered sanitized (at least for the FV's) if the tank wasn't full of beer in 48 hrs a fresh sani cycle would be run.
Personally I wouldn't trust a tank that's been sitting 'sanitized' for a week.

[claponsie]

The 2 breweries I've worked at that did this had strict time limits that a tank was considered sanitized (at least for the FV's) if the tank wasn't full of beer in 48 hrs a fresh sani cycle would be run.
Personally I wouldn't trust a tank that's been sitting 'sanitized' for a week.

I don't have a need to stretch it further than the 3-4 day mark. It would be really interesting to perform a few swab tests on a couple surfaces of a fermenter over a period of time, though. I'm a data driven person, so I tend to stay out of debates like this without having some kind of scientific marker. I was just curious about what the professionals do. Thank you all for your input!

[dick murton]

Don't forget the key word here is "sanitisation" not "sterilisation". Sanitisation means it is not likely to be completely sterile, and therefore potentially any viable bugs will have a chance to grow up in residual moisture, potentially allowing spoilage in the product. For what it is worth, all the big brewers I have worked for agree on re-sanitisation after 24 or 48 hours, depending on the company. The tendency is to allow longer times where vessels are in cold rooms, e.g. maturation or bright beer tanks, but 24 hours for FVs, or other tanks not in a cold box.

Having said all that, if your vessels are sealed and well drained, there shouldn't be much risk.

BUT, if you are able / forced by demand (or lack of) to leave them empty for that long, why take the risk ? You obviously have sufficient time to re-sanitise and keep a short window before refilling.

[ziggy13]

Great post everyone. I have a question.

I believe in our Birko literature their PAA sanitizer states it only keeps whatever you have sanitized in a sanitized state for up to 24 hours and that's with co2 pressurization as well. We are currently using a house built keg washer, so it takes a while to get the job done. We end up cleaning kegs one day, then the next day sanitizing with PAA and pressurizing with 10-15 lbs of co2, then always within 24 hours of the sanitizing cycle we fill the kegs. My question is, would we be okay filling the kegs within 48 hours, 72, or even more? Or did I read correctly that the sanitized kegs/fermenters/whatever will only "last" 24 hours, or are we worrying too much?

[claponsie]

Great post everyone. I have a question.

I believe in our Birko literature their PAA sanitizer states it only keeps whatever you have sanitized in a sanitized state for up to 24 hours and that's with co2 pressurization as well. We are currently using a house built keg washer, so it takes a while to get the job done. We end up cleaning kegs one day, then the next day sanitizing with PAA and pressurizing with 10-15 lbs of co2, then always within 24 hours of the sanitizing cycle we fill the kegs. My question is, would we be okay filling the kegs within 48 hours, 72, or even more? Or did I read correctly that the sanitized kegs/fermenters/whatever will only "last" 24 hours, or are we worrying too much?

Somebody on this board actually had a chemist perform a swab test on clean and sanitized kegs over a period of time. He found that the kegs stayed sanitary for a quite a while. Check out the thread here:

http://discussions.probrewer.com/showthread.php?43323-How-long-do-kegs-stay-sanitized&highlight=sanitizing+kegs

After we sanitize our kegs, we throw them in the cold room to help minimize any chance of bacterial growth, but it seems like the risk is pretty low to begin with.

[ziggy13]

Somebody on this board actually had a chemist perform a swab test on clean and sanitized kegs over a period of time. He found that the kegs stayed sanitary for a quite a while. Check out the thread here:

http://discussions.probrewer.com/showthread.php?43323-How-long-do-kegs-stay-sanitized&highlight=sanitizing+kegs

After we sanitize our kegs, we throw them in the cold room to help minimize any chance of bacterial growth, but it seems like the risk is pretty low to begin with.

Thank you very much for your reply and pointing this thread out. Good stuff!

[claponsie]

BUT, if you are able / forced by demand (or lack of) to leave them empty for that long, why take the risk ? You obviously have sufficient time to re-sanitise and keep a short window before refilling.

Based on the feedback from this thread, I'll probably adopt the 24-48 hour rule. The basic consensus beyond 48 hours seems to be, "It's probably safe, but why risk it?" I would love to see a study showing microbial growth over a period of time in a sealed/sanitized vessel. Until then, I'll play it safe. Our tanks aren't empty by lack of demand. Our tanks end up empty because it takes so long to fill them, and the bottleneck ends up being the brew house and brewer. I am working on offloading some of my non-brewing related responsibilities to help with this. We sell any excess kegs not sold in the taproom to a distributor. It is rare that we have an excess of kegs in the taproom, so we are not even close to demand-capped.