For example has anyone done an experiment where they either didn't wash/sterilise any equipment including the fermenter, spoon, jugs, other etc or at most they just rinsed out the equipment with water.

If so what were the results, did you get an infection, did you culture botulism, did it turn to vinegar or did it just have off flavours OR did it turn out fine.

Cleaning stuff for brewing is a real pain and I do wonder how thorough you really need to be.

5 Answers 5


TL; DR; You need to clean!

You do this for safety, repeatability, and to avoid wasting your effort. I have cleaned poorly before and wasted brews of both wine and beer, since I took a more rigorous approach I have only had 1 contaminated brew in 13 years, and that was using kit and sanitiser that were not my own.

Even if you are making a wild brew you need to clean down and scrub out all the crap and then sanitize you equipment. You only want to get into your brew what you intend to get in.

Even in breweries in Belgium where they use coolships, they make sure they are clean before introducing the wort, and blowing the air over. They also ensure that the fans are covered with fine mesh to stop flies or leaves etc being blown into the wort. They only want the micro flora and fauna to inoculate their wort, not some residual contamination hiding in a valve or seal or sitting on a fly.

Yes, you need to do the tedious cleaning our you will get biological contamination, which can lead to a number of problems:

  1. Most serious you get some from of mold, which can have mycotoxins, that can kill people.
  2. You get acetobacter contamination which will turn your whole brew to vinegar
  3. You get wild sacchromyces/other yeast strains which can lad to phenolic or other off flavours
  4. You get lactobacillus which will produce lactic acid in weakly hopped beers, and will alter the sugar consumption profile of you primary sacchromyces strain.
  5. You can get pediococuus which will turn your beer 'ropey' and will acidify your brew.
  6. Enterobacter can contaminate your brews and turn them into vomit smelling horrific messes.
  7. There are others thing that can get into your beer and produce off flavours but those are the main ones.

Most food poisoning bacteria salmonella, e.coli o157 etc... can not survive in fermenting beer past day 3 the alcohol and pH drop does their job and kill them off. Mycotoxins from a mouldy seal seating or a poorly cleaned valves are the main health danger.

All the other will just give you unintended funk, higher levels of acid, or disgusting ruined beer.

Once you have had one of these contaminations, if you are using plastic fermenters or soft rubber seals, you probably should bin the kit, or at least let it soak in bleach solution for a few hours to thoroughly sanitize. You can take all your seals and sterilise them in a pressure cooker, for 30 min.

Soft tubing will need to be sanitized as well, Brett in particular is highly tenacious and can contaminate brews weeks later. Or cause over attenuation after bottling causing the dreaded bottle bomb scenario.

If you are in a professional brewery this is taken to a even more extreme level, all vessels, hoses and unions will be cleaned with a combination of caustic and PAA. Then should be routinely checked with a ATP Bioluminescence Meter if a result after cleaning is >30 you have a big problem, it should be <10 RLU.

  • "Kill people"? Dude, relax...
    – Robert
    Commented May 28, 2018 at 2:42
  • I am not stressed, I am mearly stating facts, mycotoxins are about the only thing that is going to kill people in brewing, other than dropping 1000kg of malt on your head, or electrocution, or gas explosions. On second thoughts we should all just stop right now, this stuff is dangerous :)
    – Mr_road
    Commented May 30, 2018 at 8:19
  • So here is my follow up question: why does it matter if all my equipment is sanitized and my brewing environment is clean too, when I introduce grape or other juice from fruit harvested manually, transported in dirty trucks, pressed in un-sanitized machines, and dispatched in un-sanitized containers? What's the point of introducing contaminated content into a sanitized environment? I don't really understand the logic, unless the must gets thoroughly boiled. Commented Nov 23, 2018 at 5:36

Unfortunately, yes, it is needed. When I was starting, in my first year, I lost a lot of batches, I could say 2 from 3 batches were lost due to bad cleaning, I never figured exactly what I was not cleaning good enough, but the result was aways the same, a rotten taste and smell.


It's like with any other food preparation equipment: your stuff needs to be clean, but don't go too crazy with 100%-germ-free / kill-everything-sanitizer-from-hell.

During brewing you boil the wort for 60 to 90 minutes, that takes care of whatever may have gotten into it.

After boiling you need to be more careful. You want the yeast you pitch to be the strongest culture. It can easily overpower a few wild yeasts that float around in the air, but if you do an open fermentation you may find that the steady supply of wild yeast can overpower the yeast you pitched. Tha's why you ferment in a closed vessel with an airlock, unless you are doing a sour beer anyway.


Cleaning is definitely the least fun part (besides drinking the beer, terrible) about brewing but after a few spoiled batches I too take it almost to the extreme. The pain of dumping a batch and whole day of work does not compare to the bit of extra work of cleaning and sanitation.

I don’t think it works that simple, not cleaning a spoon doesn’t automatically mean contamination, but also the other way around, cleaning does not guarantee contamination free. It is all about minimizing risks. If you would conduct such an experiment, one time could be fine but the second time not. Not reliable enough to draw conclusions from in my opinion.


The trouble with questions like this is in our litigious world if anyone says don't clean and you poison yourself on a home brew and you live in the US you may believe you have the right to sue!!!

So I won't answer your question, i will say what i do, not as advice to you, but because i like typing.

I am lazy. I do homebrewing from kits but do mess around with and add hops to the bucket, and am about to start messing around with steeping grains and adding that to the bucket as well.

In my opinion brewing advice, which may be different to brewing reality, goes way over the top on cleaning and sterilising EVERYthing.

My cleaning routine is based on the principle that all containers the beer has to live in need the contact-with-beer surfaces sterilised shortly after use, and then to be stored away for the next use with the steriliser still in them in a sealed sterile state. Because following this principle means you always have lots of sterile and sterilising water stored, it can be used to clean bits and pieces of equipment next time.

So the main tricks are:-

  • Shortly after finishing a bottle of beer, I rinse the bottle thoroughly with very hot tap water, then add some very hot tap water, steriliser (I use level teaspoon of sodium met), cap the bottle with the sterilising water still inside and store it. I can use this sterilising water for cleaning next time I use the bottle during bottling.
  • After bottling a brew, thoroughly rinse and clean the bucket, add 2+ jugs of boiling water and steriliser (I use 2-3 heaped tablespoons of sodium met), put the lid on and shake the bucket around being careful not to point the airhole at myself, hot steam gushes out. Put on an airlock and store away with the sterilising water still inside. I can use this sterilising water for cleaning next time I use the bucket for a brew.

I have been doing this for years and only once got a kind of white mould growing on top of the beer in a bucket, but the beer still tasted good :)

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