Sanitisers
by peas_and_corn on 02-28-2007 at 06:34 am

About sanitisers

Sanitation is king in brewing. Everything that comes into contact with your brew must be sanitised to prevent undesirable microorganisms from taking a foothold in your beer. Brewers call this an infection, which sounds really offensive and conjures up images of puss-filled ulcers, but it is correct terminology - an unwanted life form of some description has 'infected' your brew.

The most important aspect of sanitation to remember is: if your gear is not CLEAN, you cannot sanitise it! In other words, you need to remove all soiling from all of your equipment, and once your equipment is spotlessly clean THEN you can sanitise it. In practise, this generally means cleaning an item well after use, storing it clean, and then immediately before use you should clean it again to remove any dust etc, before sanitising it.

Remember that there is a difference between sanitisation, disinfection and sterilisation. Precise legal definitions vary around the world and even between industries, but the United States EPA defines the terms as:

A "sanitiser" is a substance that significantly reduces the bacterial population in the inanimate environment, but does not destroy or eliminate all bacteria or other microorganisms.

A "disinfectant" is a substance that destroys or eliminates a specific species of infectious or other public health microorganism, but not necessarily bacterial spores, in the inanimate environment.

A "sterilant" is a substance that destroys or eliminates all forms of microbial life in the inanimate environment, including all forms of vegetative bacteria, bacterial spores, fungi, fungal spores, and viruses.

For our purposes most of what we do is to sanitise. This simply means we take measures to reduce microorganisms to a level low enough that they are unlikely to cause problems. Disinfecting is difficult to achieve in the home without high concentrations of nasty chemicals or specialised equipment, and high concentrations of nasty chemicals are undesirable around the brewery for obvious reasons. It can be done, but it requires a source of exceptionally clean water for rinsing off the disinfectant, or using a relatively 'friendly' disinfectant like pure alcohol. It is usually reserved for situations where desirable yeast populations are small - for example, in yeast propagation. Sterilisation usually requires the application of high temperature and pressure for an extended period of time. This is usually virtually impossible to achieve at home, it is pointless anyway unless you can seal the item it in an airtight container immediately afterwards (as the air all around contains spores and bacteria that will soon settle on your 'sterile' surface) and it is simply not required.

Generally speaking we just need to sanitise, to control the number of bugs which can come into immediate contact with our virgin wort. We do this by first removing all organic matter (soil) which can provide food and lodgings for undesirable bugs (90% of the 'sanitising' process is simply 'cleaning'). After that we generally use a sanitising chemical to significantly reduce any stubborn microbes that remain.


Choosing and using a sanitiser

There are a number of sanitisers available to the homebrewer, all of which have quite different properties. Generally we like to use a 'no-rinse' sanitiser. This simply means that the product (when used properly) will leave behind no taste, smell or harmful effects, and is approved for use in food preparation. Rinsing a 'no-rinse' sanitiser can actually introduce new contamination from the rinse water.

Which sanitiser you use is entirely up to you, your preferences, your budget and the availability of options. Some brewers remain loyal to a single option, others rotate between alternatives or use different sanitisers for different applications. All are effective, providing you adhere to the manufacturer's instructions. It is important to use sanitisers at their recommended dilution rate, no weaker, and no stronger. Home brewers often make the mistake of using too high a concentration of sanitiser - this creates a risk of toxicity or detectability in the final product, and some sanitisers (such as iodophor) are actually LESS effective at high concentrations. Never mix sanitisers together.

It is also important to allow all sanitisers to drain and dry completely if the item is not being used immediately, as most sanitisers actually become a food source once their potency has been lost. This is fine if the item is going to be used right away, but anything which is stored with 'activated' liquid sanitiser inside will become contaminated within days. Always store your equipment dry, and preferably upside down so that it can drain and won't fill with dust.


Sodium Metabisulphite

'Sodium Met' is probably the most familiar 'no-rinse' sanitiser to homebrewers. It is sold as a white powder in all homebrew shops and most supermarkets that carry a range of brewing ingredients, and it is found in most starter kits. Unfortunately, it is one of the worst sanitisers available now that so many better alternatives exist.

Sodium Met is slow to act and often used ineffectively. To use it properly, dissolve the sodium metabisulphite in the correct amount of water, as directed by the instructions, rinse all surfaces with the solution and allow to air dry. Drying is essential because this is when the sodium metabisulphite does its thing. It does not kill bacteria outright but it inhibits the growth of wild yeast. The fumes are highly irritating (particularly to asthmatics) and should not be inhaled.

It does have other uses around the brewery though. Sodium Met (as powder or in the form of Campden tablets) is sometimes added to wine or cider to halt the fermentation process before it is complete, to leave some residual sweetness in the must. It is also effective in purging chlorine AND the more stubborn chloramines from brewing water, and some brewers add a pinch or two to the mash, in the belief that it protects against certain undesirable reactions and helps to preserve the finished beer. It is also useful as a way of sanitising water to use for rinsing other cleaning or sanitising products.


Bleach

Bleach is cheap, highly effective and readily available. Its active ingredient is chlorine, as used in tap water and swimming pools, and is relatively safe at low concentrations. When used at the recommended dilution rate (10ml plain, cheap, unscented household bleach to 5L water) and allowed to fully dry, then rinsing is not required. The solution takes effect in as little as 30 seconds after contact, although 2 minutes is the EPA standard for 'instant' sanitisers. For maximum effect, match the amount of bleach with an equal amount of white vinegar ADDED TO THE DILUTED SOLUTION (NEVER add vinegar directly to bleach!). This reduces the pH and 'activates' the bleach to become a real microbe killer.

Bleach should be used with cold water as hot water neutralises it. For the same reason, rinsing should be done with hot water.

Bleach is unforgiving however, and some people have a very low threshold for detection of chlorine. If used at excessive concentrations (as is common), or not allowed to drain and fully dry it can easily be detected in the final beer. Couple this with the high level of chlorine already present in some water supplies, and its highly recognisable (and unpleasant) taste and smell, and it isn't surprising that many brewers are wary of using it around the brewery. However, used properly it is hard to go past the efficacy, price and availability of simple household bleach.

Note: Bleach should not be used on stainless steel. It causes pitting of the stainless steel surface which can give rise to the development of rust. Other sanitisers are better suited for use on stainless.


Iodophor

An Iodophor is a mixture of Iodine with a solubilising agent, sometimes phosphoric acid. Used properly it does not require rinsing. It is cheap and readily available through most good homebrew shops. It is supplied concentrated, and the brewer dilutes it to make a working concentration of 12.5 parts per million 'titratable iodine'. Usually this represents a dilution ratio of 1:1000 (or 10ml iodophor per 10 litres water), but check the label on your product as some retailers supply it diluted to different rates. Iodophor is actually less effective at higher concentrations, and at very high levels can leave a noticable taste in your beer. Consumption of very high levels over a long period of time is known to cause health problems.

Once again, Iodophor should be given 2 minutes of 'wet time', although it does not require full immersion of the item for the whole time - it is enough simply to wet the item and then leave it for 2 minutes. Spraying it with a spray bottle can be perfectly adequate. The iodophor binds with any microorganisms immediately on contact, and destroys them within the following 2 minutes. The biggest downside for iodophor is that contact with some surfaces, especially fabrics and white or clear plastics, can stain them a yellow to orange-brown colour - this is harmless but unattractive.

Iodophor used to be used to sanitise glass milk bottles and is still widely used to sanitise dairy equipment. While consumption of large quantities is toxic, the presence of trace quantities in your beer is perfectly harmless and actually adds the essential element Iodine. Used at normal dilution rates and allowed to drain freely from equipment it is one of the safest and most effective sanitisers available. It is best mixed immediately before it is needed, and always with cold water, as the iodine (the active ingredient) will break down rapidly with heat and sunlight (hence the colour change from yellow/brown to clear). The trace materials which then remain can actually provide a favourable environment for bacterial growth.


Napi-San

Napi-San is not a true sanitiser, but does have some sanitising qualities. It is basically made up of Sodium Carbonate (washing soda) and Sodium Percarbonate. Sodium Percarbonate is the active ingredient, while Sodium Carbonate is the emulsifier/detergent agent. Sodium Percarbonate breaks down into Sodium Carbonate and Hydrogen Peroxide. It is this Hydrogen Peroxide that is the sanitising agent in Nappi-San.Nappi-San requires very hot water (above 65*c ) to work effectively. The hot water allows the Peroxide to form, and do its sanitizing

Nappi-San will not stain or attack plastics, metals or glass, however you will need to rinse it off after use, although it is non-toxic and you wont die if you dont rinse.

Napi-San makes for one of the best soak cleaners available. It will readily remove organic matter (trub, yeast etc) from brewing gear, and as it does not attack materials (like bleach sometimes can), items can be left to soak for long periods of time without problems.


Hydrogen Peroxide

Hydrogen Peroxide (H2O2) is an excellent sanitiser. It is anti-bacterial and anti-microbiological, and is used in many medical and industrial applications as a sanitiser and steriliser. Hydrogen Peroxide breaks down into oxygen and water over a fairly short period of time. It uses the oxidising (burning) effect to kill biological contaminants. It is highly effective because bacteria and fungi cannot mutate and form resistance to it.

Hydrogen Peroxide is particularly good for brewing as (in diluted form) it does not attack plastics or metals, it leaves no residue, and it breaks down quickly into harmless water and oxygen, requiring no rinsing. It can be used as a soaker or spray sanitiser, and it can even be added directly to sanitise brewing water (at a rate of 0.0015% to 0.005%). As a sanitiser it is generally used at concentrations of 0.015% to 0.5%. At 2.0% to 3.0% it is classed as a disinfectant, and is often used to treat cuts (be warned, it stings like hell). 5% is the concentration found in hair bleach. At concentrations over 10% it becomes extremely hazardous to handle, it will bleach and burn skin and cause serious damage to eyes and soft tissue.

Hydrogen Peroxide is the ingredient found in the newer brewing sanitiser products such as BrewShield and Morgan's Sanitize. These products generally contain around 3% H2O2 and suggest dilution to a final working concentration of around 0.1%.

If you are diluting it for storage, it is important to use distilled (or deionised) water as the impurities in tap water will cause it to react, venting oxygen and diminishing the potency of the remaining solution. It is also suggested to add one drop of phosphoric acid for each litre of water, to keep the pH below 4.0 – this helps to prolong the life of the solution. Store it cool and dark, away from sunlight and kiddies, and in a container with a special vented cap (it will be supplied in one), as Hydrogen Peroxide constantly degrades over time, producing oxygen gas and therefore pressure. However, the reaction is normally very slow and the concentrated product (and distilled/deionised solutions) should remain effective for many years if properly stored. The reaction is accelerated greatly by heat, contamination and ultraviolet light.

Solutions for immediate use can be made up with tap water, and the resulting solution should be good for several days, but it depends a lot on the purity of your tap water. For peace of mind make up a new solution each day or two, or always use distilled water and unused portions should keep indefinitely. If it is placed in a spray bottle, keep the trigger head top slightly loose, as the pressure caused will force the liquid out through the nozzle and empty the container.

UV Light

UV ( Ultra Violet ) light is also another form of sanitiser/steriliser that is used to sterilise many forms of equipment. It is also used to sanitise water by passing the water over a UV light source.

UV does breakdown plastics so it is probably not the best method for use with plastics.

UV light can be sourced from special UV lights or from the sun. It can only work on clean surfaces.

It is not the most practical form of sanitising but does work.