I was telling a few people about this at the brewday in TOG yesterday. One of the guys that I work with was analysing how much bacteria fell in a given area (Petri dish) over a 90 minute period. He gave everyone in my lab a dish to try at home to expose for 90minutes.
I decided to expose mine while I was bottling beer as sometimes it is exposed for a while when siphoning and while in the bottling bucket. Here is a pic of what fell after 4 days in an incubator at 26 degrees.
(http://img407.imageshack.us/img407/7380/img20130415095617.jpg)
Some of it is mould and the rest is mainly caused by "skin flora (http://en.wikipedia.org/wiki/Skin_flora)" which are common to every household. One of the science girls is going to analyse it in a bacterial database later to get a specific list of the species.
The contamination concentration is proportional to the amount of airflow in the apartment/house. So any open vents, doors, fans etc will contribute more bacteria to the sample. As I was bottling I was moving around a fair bit, opening doors, washing bottles, carrying boxes in addtion to two PC's running with fans in both. So I see my sample as a kind of worst case scenario for my apartment....hopefully... ;D Definitely recommended keeping your beer covered while cooling!
Thats amazing! What particular nutient agar was that grown on?
Wouldn't mind some in the next GB!
I think its a general purpose agar mix. They also have other mixes specifically for growing yeast and other organisms but those types wasn't used for this test. All I can tell you is that it stinks and smells like science lab. ;D
Wonder what and how much of each species is in there? Will we know if this could have any effect on the end taste of the bottled beer?
These are a couple of 'blank' slants from the TOG brew day a few weeks ago. I decided to see what would happen if I made slants from vials that had not been sanitised. I think they were open a few times. The first one is mould and the second looks to be more of that "skin flora" that was showing up on the plate earlier in the thread.
(http://img15.imageshack.us/img15/3733/img1043ra.jpg)
Mmm... skin flora.
I thought the crabs ate all that kinda stuff.... ::)