Iced Coffee : Where we're at?

Last Sunday our theme at the trimestrial Home Brewing Session was 'Iced Coffee'.

Not the Frapuccino's or any other milky drinks, but the pure uncut black cold stuff, iced and iced.

I did some tests in the past.
Almost day to day 5 years ago I posted this.

Meanwhile i didn't taste anything spectacular anymore. I heard about a hundred of recipes, but was very sceptical about all of them.
Main problems are ; 1, starting at 90 degrees or more and bringing the coffee later on to iced temperature, a lot of 'negative' tastes come peeping in your cup/glass.
If you cool it quickly : There's a chance at some acidulation (or is it rancidification?) that's really not pleasant.
If you cool it slowly : There's some harshness that's really not pleasant.

2, the original flavors of your bean start drifting away over time. The longer you cool the coffee the stranger it's tasting.

3, if you start with espresso's as your base, you need too much ice or water to get a serious drink.

So, here we are at Caffenation testing some of the iced coffee's I prepared.

I had a Kenia and a (medium roasted) Espresso blend brewed on a batch brewer (Bunn ICB) that was cooled down to room temperature and the cooled in the fridge over night.
The Kenia didn't do it for us. Drinkable, but too sour and harsh.
The Espresso cold coffee was discusting all the way.

We had a filter brew on 85degrees and cooled that one over ice. Too light. Clean, but boring. It's true that a higher ratio helps for a better balanced cup, but up to today I never had one to my liking.

We had a slow cold brew (on a Hario Slow Brewer) that we cooled a bit and that one was not bad at all.

But then we also had a cold brew Kenia, prepared with a V60 the day before and chilled over night, and then served. Yes sir, the winner.
I remember my best iced drink from a couple of years ago was close to this one. I admit the main problem is that we miss a lot of flavors we find back when extracting the coffee at a higher temperature. This saying we won the Aeropress championship brewing the coffee at 78 degrees, which is almost in between very hot water and 'our' temperature. 
The cold brew I'm making is with 40 degrees 'cold' water.
I admit it's lacking some acidity, but gets very sweet and once it's cooled over night in the fridge it gives a very good mouthfeel and bourbon-liquor taste.
When picking a coffee that's clean and has enough acidity from origin, this method is very interesting.

Yesterday and today we decided not brewing the cold brew with a V60, but with a Hario slow dripper.
Why?
It's a nice demonstration tool, brews by itself and is lot of fun to use.
The Barista on duty may have it running a couple of times a day -it mostly runs 1 and a half hour per brew-, and you bet our clients do find it a very interesting to look at.
Later on it's poured in a ceramic pot and chilled in the fridge.

So, drop in one of the days for a look at this wonderful tool. And when it's not running ; maybe ask for a demo.

Writing this and meanwhile doing some research I see James H wrote about it as well last month -LINK. Interesting, but here as well we read the result is often a bit too weak and tea-like.