Does anyone have experience with an immersion chiller for fermentation. I ferment in a 25 gallon conical and would like to be able to control fermentation temperature. I thought about building a cabinet of some sort but I barely have enough time to brew and am reluctant to take on a project that large. I also thought about an upright freezer with a controller but it is hard to find one larger enough for my fermenter. Then it occurred to me that an immersion chiller might be an option. I’ve seen a couple of references to such a device but have lots of questions.
Should I use stainless or copper tubing?
What length of tubing do I need and what diameter?
Would a flat spiral design be better or should I go with a traditional cylindrical coil? Must be able to clean and sanitize.
Would an ice bath in a cooler be sufficient or should I place the “hot” coil in a chest freezer or refrigerator?
If anyone could offer any advice, I would really appreciate it.
Look at the Brewhemoth, http://brewhemoth.com/
We build an internal chiller, just what you are talking about. A quick search should show a video or two, not to mention a few discussions on facebook and various boards. Currently I am finishing up a batch of Special Bitter, 10 gallons that was held at 67 +/- 1 in a 75 degree room using one in my Brewhemoth.
I copied the Brewhemoth design for my first immersion chill coil. My second chiller was a simple straight piece folded in half twice. I would strongly suggest the stainless. I sourced mine from nybrewsupply.com
I found that the larger the chiller and the cooler the chilling water the more likely you will undershoot the temp as the residual cooling water sits in the fermenter. I have the temp probe taped and insulated on the outside and built a foam box so that I didn’t have to fight drastic temp swings from the surrounding ambient air.
I keep my chilling water at about 40F and can pretty easily drop temps down to near that.
It seems that during fermentation you’re talking about lowering the wort temperature by a few degrees (for ales anyway) over a long period of time, compared to lowering almost 150 degrees over a short period of time. This means you shouldn’t need nearly as big an IC for fermentation control. The other consideration though is chiller water temperature. A larger chiller would allow your chiller water to be closer to fermentation temperature and you’d have smaller temperature gradients in your fermenting wort.
here is a picture for an open fermentation vat with cooling coils:
If you only want to chill the beer, you should place a coil at the top of the beer. I think the best shape for the coil would be a flat spiral. This would allow the cold beer to fall to the bottom. If you want to heat and cool the beer you need something at the top and the bottom. But heating would be best done with a heating pad strapped to the cone. IMO.
I’d opt for stainless. I’m not sure about copper in an acidic environment for an extended time.
I have been happy with using a 40 foot, 1/2" OD copper coil in my 20 gallon conical. My only problem is I use my 28F chest freezer as my 5 gallon chill water reservoir (with an alcohol/water mixture). I feel I should be using a larger chill water amount at a colder temperature for perfect control.
To support what Kai said; I would also not recommend using copper in the fermenter b/c as the beer ferments, the pH drops down into the 4.4 - 4.7 range - low enough to leach copper into your beer. I’d avoid this by going with AISI 304 or 316 stainless steel to avoid corrosion.
higher pH and much shorter contact time make that less of a concern. plus the yeast probably want a little copper in their diet and will metabolize some of what might leach into the boil. Also, not scrubbing your IC after a boil, just spraying/wipeing it down really well will allow a layer of passivated material to remain on the copper which means the copper itself is not even really in contact with the boiling wort.
Well, your argument holds little water (pun intended). pH is a minor part of this issue. Talk about the pH of HCl and I would take notice. From a chemistry point, a boiling medium is far more agressive than a cold one. So it is ok for copper to enter the beer early, but not late? What’s the difference? Remember that before stainless became the brewer’s go to metal that copper was it. It is very likely that there still remain breweries that use copper fermenters.
Well, I could very well be wrong. However ‘people used to do it’ is not a great argument for anything. people used to add lead to wine cause they thought it tasted better. Doesn’t mean it’s a good idea. There still remains the issue of contact time (20-50 minutes for a chilling, 1-3 weeks for ferm control). Also the pH scale is logarithmic so that fermenting beer is about 10 times as acidic as the boiling wort.
