A Quick Guide To Homebrew Sanitising (And What Happens If You Don’t Do It)

Around six months ago I made an experimental batch of home brew without using any sanitiser.

The time’s come to open it.

homebrew sanitising: a brew that doesn't use it

Homebrew sanitising is one of those things that new brewers are warned about: if you don’t sanitise you’ll ruin your beer!

Since I made the unsanitary batch I’ve actually had an unplanned infected bottle. The beer gushed out in a torrent of foam and it smelled and tasted awful.

Luckily it was just one bottle and the rest of the batch was fine. But I’m now more convinced than ever that sanitising is an essential part of home brewing.

So before I get to the results of my experiment, I’m going to run through my own sanitising methods.

What Is Sanitising?

It’s important to distinguish between sanitising and cleaning.

Sanitising is where you kill nearly all of the bacteria and wild yeast on a surface. It’s not sterilising, which would sort out 100% of them.

For sanitising to be effective, the surface must be clean. That means completely free of dirt, beer residue, yeast debris and anything else that’s stuck to it.

The best way to ensure this is to clean as you go. Wort, yeast and hops all dry hard and fast and are tricky to remove. The good news is that they’re easily rinsed off while wet.

It’s often said that cleaning is the important part, and sanitising is just to make sure. So scrub well.

As with most things home brew, when it comes to sanitising there are many options.

In the two years I’ve been brewing I’ve used two main methods:

Sanitising With Bleach

Probably the cheapest option, normal household bleach is an effective way to clean and sanitise everything.

cleaning home brew fermenter with bleach

It’s the method proposed by Randy Mosher in Radical Brewing, where he suggests rinsing three times with tap water after bleaching.

I always felt that if you’re going to bother with carefully cleaning and sanitising everything, rinsing in ordinary untreated water defeats the purpose.

In researching this post, I discovered that this is also the view of Murl Landman of National Chemicals. You can hear more here: Basic Brewing Radio 2007, scrolling down to March 22, 2007 (Sanitizing with Iodophor).

At about 31:20 he gives a good explanation of why rinsing with water is a bad idea.

Supposedly at home brewing concentrations rinsing isn’t necessary, but I found that there were always a few bottles with a background taste of chlorine.

To eliminate that I rinsed every item with boiling water. This was especially time consuming on bottling day, and became an annoying job that spoiled my fun.

I don’t use bleach any more but it’s a good low cost option if that’s what you’re looking for.

Star San

When I discovered Star San I was very happy. It’s the best homebrew sanitiser I’ve come across so far.

star san home brewing sanitiser

This magical product covers everything.

It’s a no rinse sanitiser that’s quick and easy to use. When you mix it with water it produces a liquid with a thick head of foam. Both parts have sanitising properties.

There’s another Basic Brewing Radio show (Basic Brewing Radio 2007), this time from March 29 2007, that gives a good run down.

Charlie Talley from Five Star Chemicals (makers of Star San) explains the benefits of the product and how to use it.

Incidentally, there’s also a lot of helpful information about using bleach in that show.

More Methods

I also used alcohol for a couple of brews, but didn’t find it to be very convenient.

Here you’ll find more about that, and many of the other sanitising methods available if you’re interested.

Just before getting to the unsanitised tasting, here’s how to use Star San.

Sanitising Brewing Equipment

You only need to sanitise things that touch the wort after the boil.

First make sure the fermenter is clean. That means completely free of dirt.

empty home brew fermenter prior to sanitising

Measure out 1 oz of Star San by squeezing it into the dispenser at the top of the bottle.

measuring star san

Pour it into the fermenter and fill with cold water. I usually start the water first then tip in the sanitiser.

sanitizing filling fermenter

It forms a thick foam – that’s also an effective sanitiser.

homebrew sanitizing - fermenter filled with sanitizer

Now throw in all the equipment you use after boiling.

This includes the thermometer, hydrometer, yeast starter jar, sieve, stirring spoon etc.

Press the lid onto the foam to sanitise that as well.

Leave for a couple of minutes before removing. You can rest the items in a sanitised container, or on top of the fermenter lid.

Before pouring the sanitiser away fill a spray bottle and two or three large plastic bottles with the liquid.

The bottles are set aside until bottling day, but the spray is immediately useful.

spray bottle

Although you’ve just sanitised everything, it’s useful to be able to quickly repeat the job on commonly used items.

Before you put anything into the wort give it a quick spray.

Sanitise Bottles

On bottling day you use the set aside sanitiser to prepare the bottles and the siphon.

The bottles are easy. Pour the Star San mixture into a few of them, leave for thirty seconds, then pour into the next ones. Do that until all the bottles are ready.

pouring sanitiser into beer bottles

Of course, they must be completely clean before starting. Scrub with a bottling brush if necessary.

To sanitise the siphon you suck the Star San inside the tube. This guide to siphoning explains how it’s done.

cloudy star san

Star San keeps in bottles for a while but when it turns cloudy it’s spent and it’s time to mix some more.

That’s it. It’s very straight forward, just remember to do it.

What Happens If You Don’t Sanitise

Now the bit you’ve been patiently waiting for. What happened to my no-sanitiser brew?

Here it is:

homebrew sanitizing experiment

It looks and pours like a regular beer. It’s got a decent, although short-lived, head with very fine bubbles.

There is a strong sugary taste, which I think is the famous cider off-flavour that blighted homebrew in the past.

Sharp sweetness is the best way I can describe it. Not the balance of sweet and bitter that’s part of good beer, but an unpleasant one.

It’s a flavour I recognise from the off pints you’re sometimes served in pubs. Although not dramatically OFF, it’s bad enough to keep me using sanitiser.

What are your views on sanitising? Is it worth it?

If you use a different method, feel free to share it in the comments.

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  1. I use Star San religiously – although with paranoia might be accurate as well. I am lucky to have never had any bad batches or bottles and my fingers are crossed it stays that way. As a beginner homebrewer, I knew that sanitation was very important and something very easy I should be able to control. I use Star San thoroughly on everything for post-boil.

    What I also love about Star San – and I believe they mention it in the Basic Brewing podcast – is you can reuse it. I usually save a liter or two of the best Star San’d water after each brew or bottling session. That way, I have some to start off with on my next sanitizing process, saving some water and Star San.

    Granted, I’ve always been curious about doing an experiment such as this…

    • John

      Hi Bryan,

      Every home brew book and website out there begins with sanitisation, but I wanted to see for myself.

      People were making beer (presumably good beer) for many hundreds of years before the chemicals we use were developed.

      You’re right, it’s extremely useful that you can carry the Star San mix over between batches. It really is a great help to brewers.

      Thanks for joining in!

  2. Would UV sanitizing or ozone sanitizing work? Bleach seems fine but, you know, the taste…. and the chemicals.

    • John

      Thanks for an interesting comment. I’ve not used either of those methods before.

      UV sanitisers may well work on open surfaces such as the fermentation bucket. I expect that smaller, fiddly items, for example the inside of a racking cane, would be tricky to access. At least with a UV wand.

      Whether UV in itself is an effective home brew sanitiser I don’t know. Instinct tells me that if it’s a wand that’s safe enough to use at home, then probably not.

      Here’s an interesting article about how ozone could be used: Ozone Sanitising.

      It’d be interesting to hear from anyone with experience of these.

      • Rob Brunet

        I worked for several years for a manufacturer of UV water disinfection systems as a research engineer. UV irradiation causes photo-induced crosslinking of adjacent thymine residues in DNA, thereby preventing replication of the organism. Tthe organism is not necessarily killed, as in sterilization, but is prevented from replicating, thereby disinfecting the contaminated solution. Photo-induced crosslinking occurs for most organisms of interest with wavelengths between about 220 and 300 nm, which is in the UVC (200-280 nm) and UVB (280-320 nm) regions of the electromagnetic spectrum. UVA has almost no disinfection effect at the irradiance levels that would normally be employed.

        I do not know about the source of UV that you propose to use for surface disinfection of your brewing equipment. A blacklight or tanning lamp emits UVA radiation and would be ineffective. You should know that UVB and UVC are extremely dangerous wavelengths that can cause severe damage to eyes and exposed skin and I would not recommend using lamps emitting those wavelengths for disinfection in anything but a completely enclosed environment. The “gritty” feeling you get in your eyes when staring at an exposed welding arc is due to exposure to UV radiation and sustained exposure will blind you.

        In addition, since UV irradiation only reaches the outside surface of the article being disinfected, it is not suitable for reaching inside surfaces of tubes, airlocks, or other equipment that typically requires sterilization along with the fermenter.

        Ozone is a sterilizing agent and can be used to reach inside of various pieces of equipment. However, ozone is a gas, which makes it difficult to handle. It must be generated on-site, has a relatively short half-life when exposed to light and oxidizes mucous membranes (eyes and sinuses). It is therefore also not recommended for disinfection.

        One chemical not mentioned here is hydrogen peroxide, which could be used effectively as a sterilizing agent.

        Personally, I use iodophor. It is inexpensive, easy to use and leaves no taste in the finished beer. It requires a contact time of as little as 60 seconds if mixed at the concentration recommended on the bottle, although longer contact time doesn’t hurt and provides additional peace of mind.

        • John

          Thank you for the thorough information.

  3. Kevin S. Brady

    I might try using my dishwasher (without detergent) at its “high heat” wash setting for sanitizing bottles and other small items. The lower rack has enough prongs such that I can wash a full batch of bottles in an inverted position. Obviously, this wouldn’t work well for hard-to-clean things like siphons, etc.

    As a first-time homebrewer, I’m a bit paranoid about this. :) Guess I’ll find out in a few weeks.

    • John

      If I had a dishwasher that’s what I’d do as well. Manually sanitising bottles is a long winded job.

      The dishwasher should work well as a heat sanitiser, if the bottles are already clean inside.

      Thanks for the comment and good luck with the first batch!

  4. Carter

    I have used One-Step and never had a problem. I guess it is an oxygen (ozone?) based no rinse sanitizer. I use a pump sprayer filled with a one-step solution to sanitize my bottles and it makes it a breeze. I do like how the starsan foams though and might have to try it. Vodka is my sanitizer of choice for filling air locks but it will evaporate faster than other solutions but it is fine if it get beer, (I think this is a Mosher tip from agree with not using bleach; it stinks, certainly tastes bad and is twice as much work. Cleaning 50 + bottles is a pain…cleaning them all twice? Forget that!

    • Carter

      Sorry for bad grammar half way down I did this on my junky phone.

    • John

      Hi Carter,

      Thanks for sharing your thoughts.

      I agree about bleach. That really does add a lot of work to brew day.

      I’ll have to look out for One-step too. It sounds like a good alternative to Star San.


  5. Dan

    One-Step is a cleaner, not a sanitizer! It should be called “step one”, with step two being Star San. I almost sold all my equipment after 11 batches due to the dreaded “homebrew” taste. Once I figured it out, and used Star San, my next batch was as good as anything I’ve bought from the store. SANITIZE! And don’t think One-Step is a sanitizer. It’s just a cleaner.

    • John

      Thanks Dan.

      Yes, Star San certainly does the job well.

  6. Sue

    Interesting article, thought i would share…
    I have been homebrewing for 20 years & have never used any chemical cleaners, sanitizers or sterilizers. I thoroughly rinse bottles after use, store upside down, then on bottling day i put 2-3 inches of boiling water in each bottle, swirl & empty. I clean equipment with a chemical free, non purfumed detergent, rinse well, then douse in boiling water. I have have rarely ever had a problem in 20 years, i think i remember once or twice a bottle tasted a little different. But compared to the fuss, time, cost, & most importantly, the addition & use of toxic chemicals, boiling water is my choice! Cheers!

    • John

      Hi Sue,

      Thanks for the comment. It’s nice to hear another point of view.


  7. Umut

    Hi John

    I use citric acid (0,5 gr for 1 lt) + potassium sulphite (2 gr for 1 lt) solution for sanitising because it is impossible to find some sanitising chemicals like Star San in Istanbul.

    Do you have any idea about this citric acid + potassium sulphite solution’s effectiveness?

    • John

      Hi Umut,

      No I don’t but if you’re using it, I guess that must mean it works?

  8. Scott

    I am completely new to wine making and have a questions about sanitizing with StarSan; Once my equipment is “washed” in the solution do I wait for it to completely air dry, wipe it dry or is it ready to use even though its still wet from the StarSan?

    • John

      It’s ready to use straight away. There’s usually quite a lot of foam that never quite goes.

      • Scott

        That’s what I thought!! It’s quite crazy how you can read something so many times, but until you ask for yourself it just doesn’t seem to take hold! Thanks for the response!

  9. Mark

    I am suck in the Middle East in the middle of no where with no access to sanitizer supplies.
    Would all agree these are my best choices:
    3.Boiling water.
    I have access to sealed 5 gallon water dispenser bottles which are suppose to be clean and sanitised, I plan to use one of these with a home made air lock and apple juice.
    First time with 6 thirsty Brits counting no mention! Lol.
    Thanks for the great work. Cheers

    • John

      Hi Mark,

      You will be OK with bleach and boiling water. The bleach taste sometimes comes through to the beer, so try and rinse it off with boiled or boiling water as you go.

      Good luck!

  10. Mark

    Thank you for the comment John.

    I had some water purification tablets so used one of them. I fashioned a air lock from a water bottle and some oxygen tube. Bakers yeast has been added to the raisins and apple juice and its bubbling away quite nicely.

    I will try the bleach next time as recommended.


  11. Paul

    I’ve read a lot about having to use distilled water for mixing with Star San. Just wanted to know your thoughts on whether this is a necessary step?

    Its not mentioned anywhere in the Star San usage instructions, neither is it mentioned that it’s ineffective when it goes cloudy !!

    • John

      Hi Paul,

      I don’t believe it’s necessary, and certainly I have never used distilled water.

      I must also admit that I’ve used Star San after it’s gone cloudy and haven’t noticed any problems!

      • Paul McCarthy

        Ok thanks John that’s very useful info, I’ll stop worrying and concentrate on making beer !
        Great site by the way .

        • John


  12. Kenneth Holliday

    I know it’s been touched on, but I just want to make sure I 100% understand. When it comes to Star San I can immediately use sanitized items, including beer bottles I’m about to fill, even if they have foam from the Star San in them? I assumed from the foam that it needed to be rinsed and did so for my first batch of beer I ever made. The extra rinse step for all the bottles was very tedious and time consuming. Thanks for any clarification you can provide.

    • John

      Yes, that’s right.

      There’s no need to rinse the foam out, and you can use the kit straight after sanitising.

  13. JH

    Thanks for the article. I was going to do a similar experiment.

    Dishwasher for sanitizing bottles is the only way to fly IMHO.

    I’ve used bleach with great success. I switched to Iodophor because the bleach was leaving a white film after rinsing (may have more to do with our VERY hard water).

    And I rinse everything with municipal tap water. Never an infection problem that wasn’t directly attributable to a poorly capped bottle.