Simple question.
Besides contamination… is there any other negative reason of adding a 10lb of ice to the 3gallon boiling wort to get it to pitching temps in under 5 minutes?
Just that it probably won’t get as cool as you think. 3 gallons of water at 212F mixed with 2 gallons (16lbs) of ice at 32F would give you five gallons around 140F. Maybe a little cooler due to melting ice absorbing a lot of energy, but that’s pretty high above pitching temps. Might work well inconjuction with an icebath.
I do put it in water with some ice, but I would not call it an ice bath. My water is not very cold being in south FL. With the 10lb bag of ice, I get go from 200s to the 60s in about 5-10 minutes. I spray the unopened bag with StarSan and use a lid for the pot. I was just making sure there is not a weird chemical reaction from being too fast.
It does work? I guess my math was WAY off. I don’t know any other reason not to.
I started out with Alton Browns homebrew episode and he uses ice as his top up water so I did to. If you buy bagged ice it was sent through a UV sterilizer before freezing so contamination is not much of an issue. and 2 gallons of ice will indeed chill the wort down quickly. I used to put ice in the funnel and drain the wort through it, top up the ice as it melts. worked well.
EDIT the internet is so cool. looks like 3 parts 200* liquid + 2 parts 32* ice results in 75* liquid
I would use it IF you know that it comes from a reputable source. Water or ice CAN be a source of contamination and/or off flavors in the finished beer. I’ve used filtered tap water and spring water to top up the fermenter on many beers with no issues. I happen to have decent tap water and I make sure the chlorine has been stripped out before use.
I was wondering that. I figured with food safety these days that bagged ice would have to be treated somehow. If it they use chlorinated water though, bad juju.
good point. you would want to check that out
your math was correct if it was water at 32 degrees and not ice. ice absorbs has a specific heat that is absorbed in going from ice at 32 to water at 32. in addition the ice is probably colder than 32.
I knew that, I just didn’t realize it would absorb that much heat.
thanks for the replies. I figured it was ok if I was a gambling man with contamination. I get my ice from the Publix grocery store ice freezer. I never felt it tasted chlorinated, but I never taste tested it for off flavors. 
One point of note - ice forms at 32 degrees F, but it doesn’t stay there. The usual temp for most home freezers is 0F, so you can expect your ice to be closer to that temp range.
My practice is to use a water bath in my sink (I leave the water running and let it flow out and drain into the second basin) until my wort gets to around 100-120F, then drain the water and make an ice water bath. Once the wort gets to about 80 or so I add a frozen 20-ounce water bottle that has been sprayed down with Star-San right into the brew kettle. Each of these steps moves pretty quick, and I don’t end up wasting any ice to cool something that could have been done just as easily with a water bath.
i fell your pain bro (original poster). i took the temp of the water coming out of my hose solidly for over 5 minutes and it “got down” to 102.
HAHA exactly. I think it would be almost pointless to get an Immersion Chiller…
given that, and this neat little online calculator, 3 parts by weight water at 200 + 2 parts by weight of ice at 0 = 5 parts water at 62
EDIT Sorry forgot the link http://www.onlineconversion.com/mixing_water.htm
Not at all. With a small pump you could take water from an ice bath and pump it through an immersion chiller. With enough ice and time you could even get your wort down to lager temps.
I think it is probably OK to do it for a while, just realize it is not the best solution, and you can by all the parts at a hardware store to make an immersion chiller for about $45 or less, and it would take you 5 min. to put it together.
+1. This is my next project so I can get my 10G lager brews down to pitching temps without having to put it in the chest freezer overnight…
Dave
so if i wanted to cut down on my water use, i could just fill some plastic bottles with water, freeze them, sanitize them, and drop them in my wort instead of an IC? hell, for that matter would i even need to sanitize them? then just refreeze them when i was done?
I freeze up ten 20oz soda bottles. Sanitize with starsan right before dropping them in the wort when it hits 90*. My tap water is 88* right now so the IC does the hard part. The bottles drop 6 gallons down to less than 55* fairly quickly. That’s the easy part. ;D