Q:

Is an immersion chiller really necessary?

I have been reading here about immersion, counterflow and plate chillers and they don't seem to chill the wort much faster than my current method; ice.
Many people have stated that their chillers cool the wort to pitching temperature in 20-25 minutes.  I'm able to to chill mine to 75-80 degrees F in 25 minutes or so just filling my sink with ice and water around the brew pot.
Is the extra 5-10 minutes cooling time really going to make that big of a difference?
For the $65+ wort chiller price, I can buy  a lot of ice at the grocery, not to mention the  50 gallons of water I'll save not running the tap for 20 minutes on every batch.
Is an immersion chiller considered essential equipment or is it just another brewing gadget that isn't truly necessary for casual brewers?

A:

Is any of the advanced equipment really necessary?  No, not strictly.  But like any hobby, as we advance we acquire more gear.
Regarding the chiller in particular, if you are performing partial boils of 3 gallons or less, then you can definitely get by without a chiller.  I did just fine.  But once I switched to all grain and the full-volume boils that accompany it, there was no way I could fit my huge pot in the sink with enough ice water to chill it in a decent amount of time.  So I built an immersion chiller from 1/2" OD copper tubing.  With it I can cool my 6 post-boil gallons to pitching temperature (65F, not 75-80F), in about 15-20 minutes.  So for me, a chiller is necessary, but only because I value my time and want to improve my beer through the reduction of DMS, which can develop if you chill too slowly.  For the average partial-boil extract brewer, you can totally get by without one.
Note: if you're pitching at 75-80F, you're not doing all you can to help your yeast make good beer.  Pitch at a low temp then ramp the temps up appropriately.  Again, with partial boils you can get by chilling to 80F then add cold topping-up water to bring the full volume to 65F.  When chilling a full-volume boil, you need to get it all the way down to pitching temp.

A:

For the record too, while an ice bath can cool just as fast as an "economical" version of an immersion chiller a plate chiller is much faster.  Most plate chillers will take 5 gallons to pitching temp in less than 10 minutes.  At least, that's been my eyewitness account with friends that use them.  I plan to get one in the future too speed up my brew day.

