Flash Chiller Project

[Cvanness]

I am currently building a flash chiller as a senior design project for school (University of Houston). It will use the coils sold on this site running through an agitated ice water bath. I have a couple of general questions:

1.) Approximatly how long would it take a a domestic beer to become overcarbonated when exposed to pressures of 30 psi or more?

2.) As I understand it, for non-pasteurized beers, bacteria will begin to grow if they reach a temperature of 55 degrees or more. How long would it take for the beer to be begin to taste bad, and would the bacterial growth be stopped again if cooler temperatures are restored?

3.) I believe the circulation of the water around the coils will allow for the use of shorter coils than what would normally be used, due to convection, but I can't figure an accurate way to calculate it mathematically. Has anyone seen a system that uses a circulating bath such as this? And if so, do you know if they were able to use significantly shorter coils?

Thank you,
Chris Van Ness

[Beer Dr]

1.) Immediately, your applying the pressure to the top of the product. It's becoming over carbonated from the top down. Your drawing from the bottom of the keg, You will get to the over carbonation, or it will come to you.
2.) Draught beer in the keg is in a sterile enviorment. As soon as you tap the barrel, the product can be introduced to an enviorment that can allow bacteria to grow at any temperature. Beer stone actually will grow faster at temps lower the 38 degrees.
3.)Circulating ice water may increase your cooling capacities slightly over the ice and water just sitting, but not substantually. The only way to be able to have the coils shorter, is to have the product below 45 degrees before it enters the coil. There was a company called Cold Draft that utilized a water bath all the way to the point of dispense, but I believe they have gone out of business.
Vern

[ernestbud]

secondary fermentation will begin at 45 not 55 the keg itself would have to experience these temps for a day or two for the bad taste to set in; as for the beer in the coils it would only take a few hours to get the off-taste.over-carb would take two to three days to happen; actually depending on your coil length we generally only run about 25psi on theseand you would be better off to use a blended gas for this to reduce the risk of over carb

[Beer Dr]

Sorry ernestbud, the over carb will start to occur as soon as the high pressure is applied to the product if it is all CO2, from the top of the beer down. You just don't realize it until you get to it. The other part of the question was about bacteria growth, not secondary fermentation

[ernestbud]

sorry i may stand to be corrected;call it what you may secondary or bacteria growth= Bad taste. depending on the amount of time to empty the keg he may not have an over carb prob at all it is basically just a play on words here i was giving him general info. not to be broken down and disected