Ask The Brewmasters

maybe I am overthinking this but for a brewery that produces under 10k bbls what are some options for sterile water? mainly for use when dosing post ferm into beer.

I am up for ideas but looking primarily for real brewery experience. I was thinking boil city water then cool through the HX then hold in a vessel and deaerate for use. i]In this scenario we could use for both sani cip water and for use in actual beer if need be. my only question is what is the shelf life before you would need to start a new sterile batch?

Boiling and cooling is probably overkill.  Lots of breweries use UV inline to sterilize incoming water.  I've also seen people use in tank U.V. to keep things sterile.  I'm not the most knowledgeable about these things, but there are options out there to look into.  You would still want to do some kind of R.O. or charcoal filtering to remove impurities if necessary.

Piggy-backing off Jason's comment, it would probably be more efficient to store deaerated water in bulk and use an inline UV sterilizer on the way to your target vessel (blending into beer, etc) as needed. There's a lot of options out there and they're not too expensive.

Hey Paul,
I agree with what Jason had mentioned. Most breweries would use UV. Prior to UV, they will send their water through a carbon filter/softener/RO but these pieces are all based off of what your incoming water looks like to determine what is needed. For a 10K Barrel facility, the system just needs to be sized correctly so it is not overkill and it should be pretty cost effective.
For the time you can hold it before needing a new batch, that is determined by the sanitary design of the system most of the time. With the RO/UV systems that I typically see they are sized to provide about 1-2 days worth of water continuously so there is always drawing and replenishing happening. With good sanitary design you can likely go 1year or longer before needing to deep clean the sterile water tank. With lower quality design, you may be closer to quarterly review on the sterile water hold tank specifically.
Of course, you can always have the water tested to determine that as well.
Feel free to shoot me an email if you need any other ideas.

Hi Paul,
 TL;DR UV does not sterilize. Reasonably oversize the UV in a transfer line for what you think you need. Treat the water for turbidity and organics before the UV if this is an issue with your incoming water. Test frequently, if you can, so you don't get stuck with a bigger problem than necessary. Worry about O2 in the water you want to add to your beer.

 My theses was on DNA damage repair, including UV repair systems, I've done a bunch of peer reviewed research on microbial disinfection, and having taught this topic at undergraduate and graduate levels in medical profession and engineering contexts, so I'm concerned about some of the semantics around "sterile" especially when it comes to UV. UV can be helpful for disinfection through inactivation of bacteria and fungi (https://www.merriam-webster.com/dictionary/disinfection "the process of using a disinfectant to destroy, inactivate, or significantly reduce the concentration of pathogenic agents (such as bacteria, viruses, and fungi) ), but it does not sterilize. Per CDC (https://www.cdc.gov/infectioncontrol/guidelines/disinfection/introduction.html), "sterilization describes a process that destroys or eliminates all forms of microbial life." That's just not what UV does at reasonable doses you'd be considering. 

While a google search of UV sterilizer will give you an unending array of products, they don't actually sterilize. (Just look at some of the class action lawsuits around UV disinfection products.) Here's a good, recent review of what UV does do: https://iopscience.iop.org/article/10.35848/1347-4065/ac2b4f .  In short, UV causes oxidative and genomic damage to microbes, where, depending on the dose, it may kill some, but will largely just keep them from replicating, having damaged the DNA in such a way that it can't be copied. For the purposes of this discussion, that's what you want; the microbes not to grow again in your beer. However, if the dose isn't high enough, you may inactivate the microbes temporarily until such a time as they repair, through the microbes' innate DNA repair processes, the genomic damage blocking the copying of DNA, and they become able to replicate again. So UV dose becomes very important.

When applying UV in the context of flowing water (I wouldn't recommend just putting UV in a big tank, but recirculating past the UV in line could be an interesting option), you need to account for turbidity, dissolved oxygen, and organic compounds (thus the pre-treatment of any water as suggested by others in this thread, as any of these factors can reduce the UV reaching microbes in the flow), flow rate (if the water moves through the UV field too quickly, the microbes won't get a high enough dose), path length between the lamp and most distant bit of water (scattering or absorption of the UV), and wavelength of UV (some of the UV spectrum doesn't work as well, if at all). Be sure the system uses quartz tubes around the lamps, not glass, as glass absorbs UV. If you get a properly (over)sized unit for these parameters, you'll probably be OK, but the water is not sterile. 

When introducing process water to beer, post-ferment, pay very close attention to O2 every time before you put it in your beer. Your idea of heating then cooling it can achieve low O2, so can a de-aerated water system (pricey equipment and CO2 use). Just be sure your storage system is sanitary and keeps out O2. 

If you have a micro program that does filtration and plating, aseptically pulling a liter from your tank, filtering, plating the filter to PCA or LB or some general microbial media from the water tank weekly and cleaning when you see any abnormal microbial growth is what I would recommend. Where I worked before that's what we did, and had to clean quarterly to biannually based on findings, a little more frequent, but generally in line with what Dem said.

Please reach out with any questions. I'm happy to help.

Cheers,
Kevin

Sanitizing the water is relatively trivial. UV or sterile filtration is easy and affordable. Small deaeration systems are more cumbersome. I would not attempt post fermentation dilution without a DO meter and boiling will be the cheapest way to experiment with your process while you decide on a deaeration system. I have gotten the best results by simmering and then dropping the temp by 2C for about 30 minutes and transferring through a heat-X. Even then I am in the low ppm range and not the ppb range I would like. This is fine for rinses and mashing but not dilutions. 

Colin Kaminski
co-Author Water

As we all know, clean water is key to beer quality (and safety). There are plenty of UV inline sanitizers and in-tank UV sanitizers, available, pat pathogenic or spoilage microbes and viruses are not your only concern. Other folks in this thread advocate other clean-up steps, including activated clays (check out Claire Technologies), specialized membrane systems including RO purifiers (check out NALA membranes or CeraFilltech), ion exchangers (mixed bed or separate anion and cation exchangers), and more. If you have a sophisticated clean-up system in place, you can significantly reduce your microbial load, pesticide residues, mycotoxins and algal toxins, and most recently PFAS, the forever chemicals are getting a lot of attention. In our laboratory, we have sophisticated analytical methods that accurately measure over 60 PFAS, over 400+ pesticides, 40+ mycotoxins and other potential contaminants in water, beer, grains, and even your grey waste water stream. PFAS is the next big thing worldwide, as regulatory agencies are starting to put very strict and very low maximum levels in place, in order to reduce PFAS exposure. AOAC and FDA are currently working on establishing an official test method for accurately measuring ca. 30 PFAS in food, feed, and beverages. EPA has started to regulate PFAS in drinking water and surface water and soon in waste water.

Many have already posted here and here are a few considerations with regard to some of the suggestions given here. The water coming into your brewery will likely plate clean, as somebody already stated, but we have seen old piping systems where problems may occur.  However, UV treatment will take care of that. If you dose water into your beer, the oxygen will be an issue as well.  A deaeration system will take care of that. Beyond that, a carbon filter system at the front end will remove chlorine and other contaminants potentially present in your municipal water.  Keep in mind that water without chlorine or another replacement disinfectant will eventually start growing things.  It has been my experience that a periodic sanitizer CIP (frequency varies but ranges from weekly to monthly) of the water tank and the connected lines will prevent microorganism and algae from growing.  Boiling and cooling is not necessary. 

Frequent draw and replenishment of the sterile water will help to keep growth in the system down, but without a long term sterilant in the water, the system will eventually draw in plant air from the outside and with-it, microorganism.  I strongly believe in the principles of equalization and have seen the effects over and over.  I have traced back many mystery infections with small counts to the water system and even CO2 systems.

Hope this helps.