Here are the results of an airborn contamination test I recently performed. This intention was to quantify the dirtiness the environment I brew in. I made some petri dishes with a medium of hopped wort (like you'd get from the kettle after the boil) mixed with agar to make a gel. They were pressure cooked to sterilize them.
I then distributed the dishes around the areas I brew in and removed the covers for one hour. This allows cells and spores to settle on the nutritious agar; each viable individual then grows to colony that's visible by eye.
I tried to keep the test as representative to my brewery as possbile; hence the hopped wort (unhopped wort would have grown other organisms, but I didn't care about them since they won't infect me beer) and unheated incubation.
I was honestly shocked at how little growth there was. Zero colony forming units in my kitchen after an hour! One from inside my fermentation chamber, but I suspect this is a spurious result as it started right at the edge so it may have been a spore that got in under the cover plate. The three colonies from the area outside my fermentation chamber are a bit worrying,but not terribly surprising as this is an unfinished area under the stairs that's been used for brewing for 35 years and the exposed wood studs are stained with what may be water damage or may be some fungus that's used to living on beer spills...
Here are some more pictures.
Someone on Reddit suggested I need to do the test anaerobically or use HLP media to detect Lactobacillus and Pediococcus. Anyone know anything about that?
I then distributed the dishes around the areas I brew in and removed the covers for one hour. This allows cells and spores to settle on the nutritious agar; each viable individual then grows to colony that's visible by eye.
I tried to keep the test as representative to my brewery as possbile; hence the hopped wort (unhopped wort would have grown other organisms, but I didn't care about them since they won't infect me beer) and unheated incubation.
I was honestly shocked at how little growth there was. Zero colony forming units in my kitchen after an hour! One from inside my fermentation chamber, but I suspect this is a spurious result as it started right at the edge so it may have been a spore that got in under the cover plate. The three colonies from the area outside my fermentation chamber are a bit worrying,but not terribly surprising as this is an unfinished area under the stairs that's been used for brewing for 35 years and the exposed wood studs are stained with what may be water damage or may be some fungus that's used to living on beer spills...
Here are some more pictures.
Someone on Reddit suggested I need to do the test anaerobically or use HLP media to detect Lactobacillus and Pediococcus. Anyone know anything about that?
