Fermentation Sterilization

[Max Action]

I suppose this is more of a brewing issue than a distillation question. But why is heat sterilization the industry norm? I understand the need for heat to convert starches to sugars in grains. But in cases where that's not needed, I'd imagine there are quite a few alternatives. I've worked in the pharmaceutical industry, and there I'm used to sterilizing filtration. Is it simply that high-performance filter cartridges cost more than the gas/electric energy needed used to heat your water/wort/etc?

[MadMacaw]

I suppose this is more of a brewing issue than a distillation question. But why is heat sterilization the industry norm? I understand the need for heat to convert starches to sugars in grains. But in cases where that's not needed, I'd imagine there are quite a few alternatives. I've worked in the pharmaceutical industry, and there I'm used to sterilizing filtration. Is it simply that high-performance filter cartridges cost more than the gas/electric energy needed used to heat your water/wort/etc?

The answer is decidedly simple... as long as you do it appropriately, sterilization is a guarantee that no fouling organisms will survive to contaminate your equipment and worts/washes or any other process susceptible to contamination. Sanitization is only a reduction in these organisms so they will grow in the presence of the proper nutrition and temperature range. It is key to remember that bacteria can grow up to 100 times faster than yeast so the idea is to reduce or eliminate their original numbers sufficiently so that the yeast can out compete them in the fermentation. Nothing does this better than saturated steam for the proper contact time.

As far as sanitizers, the best one to use is peroxiacetic acid. It has a very high kill rate and can work within 30 seconds, but obviously for complete sanitization since fermenters, heat exchangers, hoses and other vessels have irregular surfaces, flow patterns and slight blind spots you would CIP for a minimum of 5 to 10 minutes on FV's and 30 minutes on heat exchangers. At first glance PPA looks very expensive, but you use so little of it it actually is very cost effective for it's superior ability. A couple of other benefits is it is environmentally safe and will not stain or/and damage hoses and gaskets like many other sanitizers, as is associated particularly with idophor use. BUT... you have to be careful using it... it is a VERY strong oxidizer (hence why it works so well) so you have to protect your skin and eyes when using it. But, you should do that with all chemicals anyway.

Eric Watson

Master Distiller

Cayman Islands Distilleries, LTD.

[Denver Distiller]

Is it simply that high-performance filter cartridges cost more than the gas/electric energy needed used to heat your water/wort/etc?

Good *od, yes. Sterile filters...coupled with all the larger pore filtration you need upstream of the sterile filters...are really expensive.

But, in terms of brewing, you have to boil the wort into order to isomerize the hops, coagulate proteins, and a few other things which includes sterilizing the wort. There are, however, relatively new wort "boiling" methods like the Merlin System from Steinecker (a brewhouse engineering and fabrication firm) that use lower temperatures or heat exchange, and therefore less energy, to accomplish the same thing.

Distillers, for the most part, don't boil their wort or mash. Cereal mashing frequently using boling, however. The fermentions are so fast that any meaningful infections are minimized, and, for course, the fermented materials are vaporized, as opposed to being put in a bottle and shipped around the world the way that beer is.

Some of the newer applications from Steinecker:

Steinecker