This might be a stupid question but is there any reason why I can't use dry ice to chill my wort? Because it's pure carbon dioxide it should be sterile. If i do it very slowly it shouldn't bubble over the top. I figure this is much cheaper then a wort chiller.
It's an interesting idea, I've never heard of I would have two concerns. First, I'm not convinced it is sterile (more of an I don't know than saying it isn't). Second you want oxygen in your wort when you pitch for healthy fermentation. I would assume if you dump dry ice in the wort you would end up with a lot of dissolved CO2, which may make it difficult to get oxygen to dissolve. I don't know if it would work well or not, but those are the issues I could see.
How much does dry ice cost and how much would it take to cool your wort? My homemade chiller cost about 60 bucks in tubing and various connectors. How many batchs of wort would it take to break even? Interesting idea.
It would take about 12 batches to equal the cost of a home made wort chiller. The O2/CO2 thing crossed my mind but I don't think it would be a problem. It might slow the fermentation by a couple of hours but I wouldn't care that much.
It's definitely not pure CO2. Maybe there is a grade that is somewhere, but not the stuff you can buy easily. I wonder if the very cold temperature (something like -100F?) makes it "close enough" to sterile though. Have you computed the amount of dry ice you would need to cool one batch? I'd be interested to see that, from an academic standpoint anyway. (I like my chiller just fine.)
If you decide to try this, have a video camera running. A chunk of dry ice dropped into boiling or near-boiling wort should be quite a show.
I use dry ice to preserve soil samples for future microbial analyses. Although those analyses are DNA analyses, I am pretty sure unicellular microbes can recover from these temps. However, the presence of microbes during the dry ice creation probably is very low. Then on top of that, that percentage that recovers from the cold when the dry ice sublimates might be low too. If I could guarantee that the surface of the dry ice did not contact anything that would contaminate, I would think it would not be a big risk for contaminating beer. But for me, cold ground water is easier to get than dry ice, and I already have a chiller. Plus, the dry ice that I get at work does come in contact with a lot of dirt, so you won't catch me trying this.
I think this should be the biggest concern. Good luck to anyone who tries this method. I'm not gonna' do it.
I've handled it before, I used to work in a biotech lab and we used it frequently. I recognize all the risks when using it, I'm trying currently to figure out how to add it without creating a geyser of CO2/wort.
My "best" suggestion was to thrown in the ice and cover the fermenter with the lid to prevent the geyser. Clearly the person that suggested this has never made a dry ice bomb.
What about a dry ice bath instead of the traditional kind? No actual wort contact. DISCLAIMER: I've never handled dry ice.
The water in a dry ice bath and regular ice bath will be the same temperature (about 32). The dry ice bath won't get the water below freezing temp. And regular ice is cheaper and easier to use.
