I was wonder that it said to cover the wort while chilling, but if your using a chiller how is that possible? Or do you cover it right after you get it down to pitching temp?
My chiller has the inlet and outlet pipe sections above the perimeter of the coils, thus I can put my lid over about 80% of the brew kettle while chilling. Is your's similar?
My inlet and outlet pipes stick out of the kettle so if I put my lid on it then it doesn't close completely.
I do what @Mothergoose03 suggested. As the temp drops i set my sanitized lid to cover as much as possible, and then completely once I remove the chiller and am preparing to transfer to the fermenter
I keep it about 80% covered, as I'm faced with the same obstacles. You could modify your lid, modify your chiller, or, less elegantly but more practically tear off some aluminum foil to cover the gap, if you have concerns about cold-side contamination. But this is one where I have decided to roll the dice and assume the odds of infection from this short time of vulnerability are pretty low, especially because soon after that wort is cool I will stack the deck by pitching copious amounts of viable yeast to outcompete any interlopers who made their way into my cooling wort.
I get mine 80% covered then soak some paper towels in Star San and drape them over the openings... probably overkill but who knows.
I notched my lid (using a diamond wheel on a Dremel-like tool) so that the input/output of the immersion chiller can stick through the closed lid. It's a fairly straightforward job (wear eye protection!). Here's a commercial version of what I'm talking about.
At How to Prevent DMS in Beer the following question was asked in the comments, “did you cover the kettle when you did the hopstand? i have heard anecdotally that covering the fermenter during a stand would not allow the smm/dms to volatize and it will catch on the kettle lid and drip back down. but it seems like you are inviting lord knows what into your wort if you keep it uncovered for a 60 min” Dan Pixley, a Milk The Funk Wiki contributor replied, in part, “In our practical recommendations for preventing DMS formation (if it is a problem), we advise trying to cool the wort openly until around 60-70°C (140°-158°F), which is still hot enough to keep the wort pasteurized, and then closing the system to prevent contamination before the temperature drops below 60°C (140°). See the “Avoiding DMS” section on the MTF wiki.” If the primary reason for covering when cooling is to help prevent nasties from getting in the kettle, would it be effective to cool uncovered to about 145°, then cover the kettle (and surround the immersion chiller tubes) with a towel that was soaked in sanitizer and wrung out? Is a towel too porous....or is there a temperature (maybe near 140°) that renders StarSan ineffective?
Wouldn't aluminum foil be easier than a towel? There's no need to soak the foil in sanitizer, the point is to block dust and I guess insects from getting into the wort. (With a towel I guess you could soak in StarSan because the towel itself might be shedding lint, but I'm a little hesitant because I personally wouldn't want StarSan, which is very low pH, in prolonged contact with my copper wort chiller. If you have a steel wort chiller, I guess it would make sense. I doubt there's anything about elevated temperature that would render StarSan ineffective for your purposes, since it is simply a strong acid, but I honestly don't know for sure.) Edited to add: Being a pedant, I looked it up, and phosphoric acid is actually a weak acid in the technical sense. But it's a strong acid in the colloquial sense of being very low pH.
Ok, not trying to be controversial. This seems like an absolute ton of mental energy for something that is relatively low risk. Back when I had an immersion chiller, now have a plate chiller, I never gave it a second thought that I wasn't covered 100% during chilling. We all make decisions regarding what is and is not important. I believe in focusing on the postive, what makes a better product, not what can go wrong. After years of brewing, I've never had an infection; I do understand sanitation practices, it's just intuitive now. If leaving it uncovered truly bothers you, make it a closed system, plate chiller with pump & closed loop plumbing, or hard mount your immersion chiller.
Yeah, I kind of didn't want to say anything, but I share @InVinoVeritas's skepticism that the effort is worth it. I've never covered my wort at all while it's chilling, and I've never noticed an infection. The thing is that I brew indoors, I almost never have fruit flies in my apartment (and if I happened to see one on brew day, I would certainly take more precautions than usual), and I brew a fair number of sour beers. So my priorities don't necessarily translate to other brewers' situations. That said, even when I'm brewing a clean beer, I never cover the wort while it's chilling. I like to be able to stir the wort periodically to speed up the cooling process, and as I said I've never experienced any negative consequences from leaving the lid off.
Agree. I use an ice bath to chill wort, and it kinda needs to be uncovered to let the heat out of the top. I’m chilling indoors tho. Never had an infection. FWIW
I’m with the skeptics. 100s of batches outside with the top off for 40 minutes to an hour. Never contaminated
