No-chill & first wort hopping flavors

In an attempt to reduce my water use (California being in serious drought conditions) I've tried replacing my immersion chiller and its 25G of cooling water per 10G batch*, with no-chill.

While the process has been very easy, I am finding that everything comes out with the characteristic first wort hop flavors - presumably from the slow (albeit reversed) transition through the 160-212F range that produce them between mash and boil. While I don't dislike these flavors when that's what I'm going for, there are beers where I don't want them. I've tried using a hop-sock to minimize the hops left in the wort in the no-chill container, but by the end of the boil the hop-chemistry is already in solution.

Is anyone else experiencing the same thing? Any ideas? I've contemplated doing a partial chill just to get below 160F which would take much less water, but that puts me right in the danger zone for contamination and removes the sterilizing properties of the boiling wort in the no-chill container (though I do thoroughly clean/sanitize it already, so it should be OK).

* I have also tried using the chiller water for other things, but with double-batch brew days, no garden, and the brewery being 100 yards away from and 20 feet below the washing machine, I just don't have a use for 50G of water.

Move your aroma hops a bit back in the boil (if at 5 min, move to 10). Firstly, you'll remove those essential oils that continue to get into the beer. Secondly, once you hit 170-175, you are no longer extracting alpha acid.

Really just depends on what you are going for. What you are describing sounds more like associated whirlpool flavor and not first Wort. First Wort's advantage is retention of aroma/flavor from the hops while increasing (albeit smoother) bittering. Is the bittering the issue or the flavor/aroma?

There's a vary particular flavor that goes with first wort hopping (which is what I'm guessing people refer to as the "smoother" bitterness), but there are some brews that I don't want that flavor with because it overwhelms other flavors I'm trying to get.

It's definitely the FWH flavor though - it's the same as I got previously with brews I FWH-ed and chilled.

No idea. It doesn't make logical sense to be the same flavor from a very different process. I'm not saying it doesn't taste that way, not at all. It just doesn't make sense from a chemical point of view as those volatile proteins should all be long gone.

If you do a partial chill down to 160 you could always toss the beer in fermentors and cap them. If your sanitation is good, I assure you it will be fine. I've left beer without yeast for as much as 24 hours w/o ill effect

I'd say you're getting hop-stand flavors, which might just be a lot like FWH flavors.