If cleanliness is next to Godliness then we as home brewers should be approaching the sanitising and sterilisation of our brewing equipment with saintly vigour. Although cleaning is not the most enjoyable part of the hobby its importance to the brewing of top quality beer cannot be understated. The last thing any brewer wants is to brew a batch of beer and then have it spoil due to an avoidable contamination. Hopefully by reading this home brewers guide to cleaning and sanitising you will avoid some hygiene horrors!
The trouble I find with cleaning is where do you begin?
Perhaps a good place to start is to define what we mean by the terms sanitised and sterilised. A vessel or piece of equipment that has been sanitised is something that has been subjected to a process where any and all surface soil has been removed. The vessel is clean or sanitised but this is not to say that the equipment or vessel is sterile as this requires some form of treatment to remove any microbiological contamination. Therefore equipment that has been sanitised can be defined as being free from visible dirt whereas equipment that has been both sanitised and sterilised is free of visible dirt and any sources of potential microbiological contamination.
By breaking the process into sanitising and sterilisation it allows us to simplify what we do and define our equipment by what needs to be sanitised and what needs to be both sanitised and sterilised. It is good brewing practice to clean all equipment but it is not essential to sterilise every bit of equipment that you own. If you consider that anything up to and including the wort boiler needs to be sanitised only, because the boiling stage effectively sterilises the wort prior to fermentation, it therefore follows that anything after the wort boiler which comes into contact with the wort needs to be sanitised and sterile to prevent the wort from being contaminated by spoilage micro-organisms. Therefore mashing vessels and wort boilers should be sanitised after use whereas fermentation equipment, bottles and bottling equipment all need to be sanitised and sterilised prior to contact with wort and beer.
Cleaning should follow a simple and basic pattern of rinsing, sanitising and sterilising. The rinse, with clean water, will essentially remove any excess soil from brewing equipment in preparation for the application of a cleaning agent which will then effectively sanitise your equipment. The rinse is an important step and should not be avoided as any excess soil, which could have been removed but has not, will reduce the effectiveness of your sanitising agent. The rinse is also far more effective if it is done as soon as possible after you have finished using the equipment. Don’t be tempted to leave it overnight as this just allows the soil to dry onto the surface making it harder to remove.
Once the rinse has been done sanitise with an effective sanitising agent, that is one that has some surfactant properties which helps to degrease surfaces as well as remove any stubborn surface soil. It is common after sanitising to rinse with cold water before the final sterilising stage. Sterilisation of brewing equipment can be done by chemical or heat treatment or both if required. There are a number of sterilising agents available to the home brewer and the two most commonly employed are sodium metabisulphite and sodium hypochlorite, household bleach to you and me. Their application is discussed in more detail later in this article. Finally heat treatment can be used as a method of sterilisation by itself or in conjunction with a chemical steriliser as a belt and braces approach to sterilising equipment. However, if you do use a chemical steriliser be careful to rinse any equipment thoroughly before subjecting to any heat treatment. The most effective heat treatment is autoclaving which is boiling under high pressure. The action of an autoclave can be replicated at home by using a pressure cooker however this is only suitable for small pieces of equipment. Some home brewers have been known to sterilise bottles by heating them in a domestic oven and this can be effective but great care must be taken when doing this as the bottles can easily break. Once you have cleaned and sterilised any equipment it is recommended that you use it immediately as long term exposure to air will render the entire process worthless.
There are three main chemical agents that home brewers use to clean and sterilise these are discussed in a little more detail below.
Sodium Metabisulphate is often used by home-brewers as a steriliser or preservative as it attacks and kills certain spoilage micro-organisms. It works by releasing sulphur dioxide which is toxic to some micro-organisms. It has no cleaning power so is not suitable for use on highly soiled brewing equipment but is good for light sterilising activities on pre-cleaned equipment. It can also be added to beer prior to bottling to inhibit microbial growth.
Sodium carbonate or common washing soda is a fantastic, and cheap, sanitiser which can be used by home brewers. When dissolved in hot water it acts as a sanitiser de-greasing brewing equipment and cleaning heavily soiled brewing equipment. It has no sterilising properties so to ensure brewing equipment is free from potential spoilage micro-organisms a steriliser such as sodium metabisulphite should be employed.
Sodium hypochlorite is more commonly known as household bleach and it can be used as a cheap combined sanitiser and steriliser in home-brewing. The sterilising properties of sodium hypochlorite is due to the release of chlorine which reacts with water to produce hypochlorus acid which is a strong oxidising agent and highly toxic to micro-organisms. Plain household bleach can be used to clean and sterilise heavily soiled brewing equipment but it is essential that the equipment is rinsed thoroughly before use to prevent any residues of the bleach from tainting the final beer. One thing to bear in mind when using household bleach is to use non-scented versions as it has been known for the aroma of the bleach to linger and contaminate the beer.
We hope that you have found this quick home brewers guide to cleaning and sanitising useful. If you have any additional tips that you use and would like to share feel free to comment below.
Until next time cheers and beers.