Sterilizing

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 thru the nozzle and empty the container.

If you get bored with brewing, H2O2 can also be used as rocket fuel.

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Genghis77 said:

I asked the same question a couple weeks ago. Did a little research and according to the FDA, a 7-1/2% solution of hydrogen peroxide is a steralant (60 minutes) and a high level disinfectant (10 minutes). The action is oxidation to accomplish the effects. The only by-products are water and oxygen. But, I cannot attest to weather it might cause off flavor. I use a 3% as a mouth wash and can say it does have a taste. No one seems to have tried it though, so I am assuming there is a reason, as we aren't the first to think of it. And it is widely usedin the food industry.

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david_42 said:

It won't leave any taste once it has all broken down into water & O2. That makes it good for food containers. I think part of the problem is cost and part of the problem is, it is unstable. Not in a dangerous way, it just decomposes over time.

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Genghis77 said:

Pure hydrogen peroxide was once used as a rocket fuel. 3% is cheap enough, but not the steralant found with 7-1/2% (available through hospital supplies), and that likely to get costly. Hydrogen peroxide is also used to aid in seed germination. I suspect that that may be related to why not used in brewing. I think there is a reason beyond just cost, but nowhere seems to be utilized in relation to brewing. I refer to the taste as soapy, but that is due to the bubbling action mainly. Makes a great mouth wash, only have had two cavities in 62 years.

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