So I just made my 1st 5 gallon batch this weekend (no more Mr. Beer for me!) - a heffeweizen.
Because I don't have a wort chiller I did an ice bath and it took me about 45 before I got it cool enough to pitch my yeast (pitched and fermenting @ 62).
I've read that if you take too long to cool the wort you risk veggie flavors in the beer. When I make my next batch - is there a time goal that I should be shooting for when cooling my wort? Is 45 minutes too long?
45 minutes is totally fine. Lots of people here do no-chill, or let things sit overnight to chill, and have had no problems. Wort chillers are nice and speed things up, but if you're cool with waiting 45 minutes, you're good to go.
chilling the wort rapidly is mostly used to produce "cold break" which is a participate the is formed from the coagulation of proteins still in the wort. the faster this happens the better chance you have of the cold break falling out of solution. This helps with fermentation as well as clarity of the beer. if too much cold break is in solution chill haze will occur which is a haze formed from the residual protein in the finished beer when the beer is cooled down. This is only a optical issue and will cause the beer to look hazy but not taste any differently for the most part. Ideally you want to cool your beer instantly, but usually anywhere from half an hour to 45 minutes is a good ball park. If you notice chill haze in your beer try cooling it down faster.
Most recommend getting the temperature down below roughly 160F as quickly as possible. This can happen pretty quick with an ice bath if you've got a big tub. After you get it to the lower temperature range there is less concern about off flavors from slower cooling. If you're doing a smaller wort and adding to clean water in the fermenter you can use colder water to get the temp down quicker. If it's a full 5 gal boil the best method for homebrewers is generally immersion chiller. Lots of options for cooling but that's part of the fun. Enjoy.
Agree with freeflydude. Although I have heard 140F was the number the point is chilling down those first 50 to 70 degrees quickly is what matters. After that the rest of the chilling can take longer without harming the wort/beer. In the summer my ground water is warm enough that I can get to 75F fairly quickly but it would take forever to get to pitching temp of about 65F. Often I will put my fermenter into my temp controlled freezer set at 65F and let it cool the rest of the way there. Then I aerate and pitch my yeast. Works fine.