The document discusses using chlorine dioxide as a safer and more effective alternative to traditional sanitizers like iodophor in breweries. It can sanitize all brewing equipment at low concentrations of 50-100 ppm without flavoring the beer. Chlorine dioxide also provides a new method for washing yeast by killing undesirable microorganisms through oxidation without stressing the yeast as much as traditional acid washing.

1. for use in Breweries
75
Activ8H2O products are designed to be safe
for people and the environment, extremely effective and
to reduce water purification and disinfection costs.
Clean Oxide 75, is our flagship product and is a 0.75% (7500mg/L) solution of chlorine dioxide in
water, which is generated by mixing two precursor solutions. Clean Oxide 75 is bio-degradable hence
also environmentally friendly. It is a broad spectrum disinfectant affective against algae, bacteria
spores, fungi, protozoa and viruses.
CleanOxide for use in Breweries
The post-rinse sanitizer of choice for many brewers is iodophor. Iodophor sanitizers are iodine based
and are extremely effective at destroying beer contaminating organisms such as lactobacillus, mould,
pediococcus and wild yeast at 12.5-25 active parts per million (ppm) of titratable iodine.
A problem, however, can occur with iodophor if the amount used is not accurately measured. For
a 1.75% titratable iodine concentrate, no more than 30 mls per 19 ltrs of water should be used
to achieve 25 ppm active. Overusing iodophor serves only to flavour beer and does not offer any
additional microbiocidal effect.
A post-rinse sanitizer which is not iodine based has started gaining acceptance with craft brewers.
Chlorine dioxide (ClO2), like iodophor, is very effective at destroying spore forming organisms at low
active parts per million (ppm) levels and does not flavour beer when used properly. Unlike iodophor,
however, the amount used is typically not as critical both in terms of microbial reduction and
flavouring beer. In other words, you will still get an effective kill at an active level of
50-100 ppm ClO2 while maintaining a minimal or non-existent flavour profile.
www.activ8h2o.com.au
M: 0430 543 439
E: darren@activ8h2o.com.au

2. Remember: Sodium Chlorite is not Sodium Hypochlorite!
Mention the words “chlorine” and “sanitizing” in the same breath around most brewers and their response is, normally,
“It will flavour my beer.” (This usually comes from the same person who taints his / her brew with iodophor). In the case
of sodium hypochlorite bleach, they are correct. As little as 1-2 ppm active hypochlorite is detectable in drinking water.
Triple rinsing is necessary to remove bleach from brewing equipment and bottles so as not to flavour the beer with
chlorine. Therefore, post-rinse sanitizing equipment and bottles is not recommended with hypochlorite bleach.
Conversely, chlorine dioxide is ideal for sanitizing after the cleaner has been rinsed. Chlorine dioxide removes phenolic
tastes and odours from water and does not form trihalomethanes or chlorophenols. This is very important to the brewer
because these compounds are extremely detrimental to beer, not to mention the toxicity to humans or the environment.
Chlorine dioxide is also used to remove cyanides, sulphides, aldehydes and mercaptans from water. These compounds
are unfavourable for beer, too. That’s great, you say, but what is chlorine dioxide?.
Chlorine dioxide can be used to sanitize all brewing equipment that comes in contact with beer, from the heat exchanger
to fermenters to the keg or bottle and everything in between.
For heat exchangers, open fermenters, secondary fermenters, Zuni’s, serving/bright tanks and kegs, a 50-100 active ppm
solution of chlorine dioxide is recommended for post-rinse sanitizing. The solution is normally either pumped through
spray balls (like CIP), or in the case of open fermenters, sprayed with a pump-up sprayer just before the beer is pumped
over to the fermenter being sanitized. Again, there is no danger of flavouring beer if the proper amount of sanitizer is
used. The spore-formers such as yeast and mould cannot develop immunity to the oxidation of the chlorine dioxide,
which makes it an ideal sanitizer for the brewer.
Also Chlorine Dioxide is a new method of washing yeast
The “tried and true” method of washing yeast utilizes phosphoric acid (H3PO4) to acidify the yeast slurry to around
pH 2, where it is held for a given amount of time, ranging from two hours to overnight. In theory, undesirable organisms
are destroyed by the low pH and trub is removed from the yeast. The healthy yeast remains suspended and is used for
pitching, while dead cells and trub collect at the bottom of the washing vessel.
However, there are several problems with acid-washing. It reduces the populations of most wort-spoiling bacteria, but
is less successful with beer-spoilers such as lactic-acid bacteria, and is generally not effective on wild yeasts and moulds.
Further, the low pH tends to stress the yeast, and for this reason most breweries wash with acid only rarely. Recently,
a few breweries have begun using an acid-free wash that allows them to wash their yeast on a regular basis.
An Alternative Method
Chlorine dioxide (ClO2) has been used for decades to disinfect drinking water. In this scenario, chlorine dioxide kills
by penetrating the hydrophobic region of the bacterial membrane and oxidizing it. Chlorine dioxide reacts with
sulphur-containing amino acids, which form cell membranes. The proteins get destroyed, the membrane ruptures and
the organism dies.
Chlorine dioxide is relatively new to the brewing industry. It is gaining acceptance as a post-rinse sanitizer, but is not
widely-recognized as a yeast-washing agent. Given what is known about it, however, it makes sense that it might be an
effective, economical and safe alternative to phosphoric acid.
Chlorine dioxide has (in theory) over 2.5 times more oxidation capacity than elemental chlorine but does not have a
chlorine-like flavour profile. Chlorine dioxide does not form trihalomethanes, as does sodium hypochlorite
(household bleach) and iodophors, and breaks down to innocuous compounds, namely table salt and water.
M: 0430 543 439
E: darren@activ8h2o.com.au