Why Sanitise? Let’s Find Out

Brewing instructors constantly drum home the importance of sanitising. But is it really necessary?

why sanitise - fermenter filled with sanitiser

Neil at Mash Sparge Boil, a now defunct home brewing blog, published the results of a poll that suggest infections in beer are rare. What’s more, if they do occur they almost never repeat.

He made the point that continual reminders to clean and sanitise mean that cleanliness is part of every home brewer’s method. In this environment it’s difficult for infections to get going.

As far as I know I’ve never had an infected brew. By this I mean that I haven’t suffered an infection that damaged the taste or appearance enough to notice.

I put this down to rigorous sanitising; during my early batches of home brew I developed obsessive habits that have stuck.

On brew day I keep a bottle of Star San handy and spray everything before use. This includes the thermoter, hydrometer and even my hands.

However, I’ve noticed that when oversights do happen (for example, if I touch the mouth of a bottle or the inside of a bottle cap before sealing) the beer survives.

Even when brewing with other people, where it’s difficult to make sure everyone handling sensitive equipment is sanitised, the beer comes out OK.

This and the Mash Sparge Boil survey have left me asking : why sanitise at all?

Why Sanitise? The Arguments In Favour

Five Star Chemicals, the makers of Star San, claim:

Cleaning Really Does Matter

As all Home Brewers know, many things that go into making great beer, including ingredients, styles, and methods. If you don’t properly clean and sanitize your equipment…….


But they don’t offer hard evidence.

Ron Bowden describes the situation more clearly in The Lazy Brewer:

When you brew you provide a friendly environment for a particular micro-organism – yeast – to ferment the wort and convert the sugars in it to alcohol.

This environment is also very inviting to all sorts of bugs you very much do not want. You want one particular yeast and none other.

He goes on to explain that there are many varieties of bacteria, not to mention over a thousand species of wild yeast, that are as tempted by fresh wort as brewing yeast are. But instead of turning it into beer, they make it foam, smell or taste bad.

Do home brewers need to sanitise so much?

It intuitively makes sense that because beer is stored for long periods of time it has to be free of infection. On the other hand, some things cast doubt on this accepted fact.

When thinking of historic brewing practice, I find it hard to equate today’s rigorous sanitising culture with the way things were done before.

How do you sanitise a wooden stirring spoon?

Similarly, my visits to commercial breweries have lead me to question the feasibility of sanitising a factory with the same level of detail that I apply to my own equipment and workspace.

My Sanitising Experiment

With these doubts in mind I decided to experiment and brewed a small batch of beer without any form of sanitising.

why sanitise grains of malt in pot

I started with a stove top mash of pilsner malt.

why sanitise mashing the grains

As I heated the pan I was still brewing as normal – you don’t sanitise anything before the boil anyway.

why sanitise boiling wort

After cooling, I poured the wort into a non-sanitised bottle.

why sanitise pouring beer into fermenter

The lack of sanitising sped up the brew significantly. I grabbed everything as and when required, and rehydrated the yeast in a jar straight from the shelf, in ordinary tap water that wasn’t pre-boiled.

why sanitise fermenter filled with beer

I covered the wort with foil. An airlock is a sealing device that is unnecessary in this unsanitary brew.

why sanitise fermenting beer in a glass jar

I realise that sanitising is important in brewing and don’t dispute that.

However, in keeping with the idea that only by doing something can you learn and understand it, I’m interested to see what this experiment reveals.

I’ll report back soon.

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  1. Chris

    So, what happened? Did it taste like beer? Vinegar? Medicine? Was this never updated because you’ve since died of botulism, and this blog entry is your final message to the world? What happened?

    • John

      Ha! No, I’m still here.

      The end result was a bit of an anticlimax. The beer didn’t turn out great (it had an acidy sweet taste), but I’ve had better infections from sanitised batches.

      I wrote about opening the beer at the bottom of this post.

      • Chris

        Interesting. So perhaps a more statistically significant series of tests would find fewer bad batches with sanitation – or perhaps it would be a wash.

        Alcohol is of course itself a disinfectant, and bacteria can force out competitors with strategies like producing alcohol. Which dominates in nature is all about fitness, so perhaps the right wort mixture for a specific yeast strain could make sanitation irrelevant.

        • John

          That’s an interesting theory but you’re right, one test beer’s not enough to draw any conclusions.

          I’m not going to stop sanitising though. For me, it encourages cleanliness in general which is possibly more important than sanitising itself.