In homebrewing
cleanliness is indeed next to godliness. Your equipment should be clean!!!
Any piece of equipment or hardware which comes in contact with the wort
after it has cooled down to below ~120° F should be cleaned AND sanitized.
Sterilize
and sanitize are two terms which are often used more or less interchangeably
in homebrewing books. These terms, however, do not mean the same thing!
To sterilize
is to kill off all (100%) of the bacteria, yeast and mold as well as
their spores. In general, sterilization requires the use of an autoclave
and/or some extremely nasty and hazardous chemical agents. In a homebrewing
environment true sterilization would be extremely difficult.
To sanitize
is to kill off most of the bacteria, yeast and mold but not necessarily
their spores which are particularly difficult to kill. In most cases, in
the homebrewing environment one sanitizes rather than sterilizes.
For the homebrewer
the idea behind sanitization is to greatly reduce the number of unwanted
microbes present in the wort thereby buying time for the yeast to gain a
foothold. Once the yeast are established their metabolism will alter the
environment such that the unwanted microbes cannot gain a foothold. This
is why is it so important to pitch a large number of strong, healthy yeast;
there needs to be a sufficient quantity of healthy yeast present in the
wort to "muscle out" the unwanted microbes also trying to get
established there.
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Common Sanitizers:
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Boiling
water - Boiling
equipment in water for 20-30 minutes is a pretty effective sanitizer.
Note, however, that the boiling point of water is depressed with increasing
elevation. One should, therefore, increase the boiling time accordingly
when using this method of sanitization at elevations considerably
above mean sea level.
Use of a pressure cooker
at 15 psi for 15 minutes is an effective sterilizer not unlike the
autoclaves used in microbiology labs. A pressure cooker is highly
recommended for canning wort for later use as yeast starters.
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Alcohol
- Alcohol is an effective sanitizer. However, although alcohol kills
most yeast and bacteria on contact it is quite ineffective against
some spore-forming microbes (Fix and Fix, 1997). Fix and Fix also
note that low molecular weight alcohols such as methyl are not effective
sanitizers whereas high molecular weight alcohols such as isopropyl
are quite effective. Ethanol is nearly as effective a sanitizer as
isopropyl is. Contrary to what one might think 100% alcohol (200 proof)
is not as effective a sanitizer as an alcohol having 20-30% water
(i.e. 70-80% alcohol or 140-160 proof). Without the presence of water,
alcohol cannot denature certain proteins present in microbes, thereby
diminishing its sanitization power (Fix and Fix, 1997).
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Bleach
(unscented) - 2
tablespoons (29.6 ml) per 5 gallons. Bleach MUST be rinsed with lots
of hot water. Although bleach is inexpensive as well as it is not
very environmentally friendly and it is water use intensive. To be
an effective sanitizer, objects should be in contact with the bleach
for ~30 minutes. Note that bleach should NOT be used on stainless
steel equipment. Bleach can pit stainless steel resulting in areas
that are difficult to clean and sanitize and thus, could eventually
harbor wild yeast and/or beer spoiling bacteria.
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Iodophor
- 1 tablespoon (14.8 ml) or 1/2 fluid oz. per 5 gallons.* The manufacturers
of Iodophor suggest that a contact time of only two minutes is sufficient.
Fix and Fix (1997) note, however, that in practice a contact time
of five minutes is required for proper sanitization especially if
spore-forming yeast are present. Fix and Fix also point out that Iodophor
should not be employed at elevated temperatures; the sanitizing power
of Iodophor decreases at temperatures above room temperature. Iodophor
does not require rinsing and may be air dried. At the recommended
concentration Iodophor is not harmful to stainless steel. Iodophor
is Iodine-based and can permanently discolor tubing and other equipment,
particularly plastic equipment.
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*These directions are for B-T-F Iodophor Sanitizer. Since iodophor
is not a proprietary product, it may be available varying original
strengths depending upon the manufacturer. One should following the
directions given by the respective manufacturer. The correct concentration
should be 12.5 ppm for a no rinse solution or 25 ppm for rinse required
solution.
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One-step
- 1 tablespoon of this powder per 5 gallons. One-step is a cleanser
and a sanitizer. According to the manufacturer One-step sanitizes
essentially on contact. However, I would recommend using a contact
time of about 5 minutes just to be on the safe side. This sanitizer
is colorless, odorless, does not require rinsing and is environmentally
friendly. I am very pleased with this sanitizer!
Note that there is a
variety of One-step which does require rinsing. When purchasing One-step
you need to make sure you are getting the variety you want be it rinse
or no-rinse.
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Other
- A number of other no-rinse sanitizers are on the market. I have
heard good things about Star San and C-Brite. However, I have had
no personal experience with these sanitizers so I can make no recommendations
regarding contact times or how effective they are at sanitization.
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Fix, G.J. and
Fix, L.A., 1997, An Analysis of Brewing Techniques: Boulder, Colorado, Brewers
Publications, 192 p.
