First brew: 160 F, 60 - 70 sec. A nice combination of tastes, vegetal, green, a bit peachy and sweet, umami, ... Smells great, like dry leaves!
Second brew: 165 F, 25 sec. Similar as before, very nice.
Third brew: 170 F, 60 sec. Less intensive, but still very nice combination of tastes.
First brew: 160 F. I first tried 90 sec, but then I reduced first brew time to 70 sec which gave me better results. Very vegetal, green, algae, umami taste, a bit bitter, there is a hint of something more floral underneath. I don't like this taste very much, but it is bearable and somehow intriguing... Doesn't smell as nice as #3.
Second brew: 165 F, 25 sec. Very nice combination of tastes, vegetal and grassy, this is what I associate with "typical sencha taste", a bit sweet, a bit bitter and astringent, great!
Third brew: 170 F, 60 sec. Less intensive, a bit more bitter, but otherwise similar to second brew.
As a newbie in the world of green tea I was pleasantly surprised by the tastes and the differences between them. I tried using roughly the same brewing parameters for all teas, but I know that I could further improve the results by adapting them for each tea. But all tested teas were much better than the occasional sencha I bought previously in local shops.
I like #1 the most, it was really enjoyable. Unfortunately, I couldn't really enjoy the #2, somehow I don't like the flavor profile and I should probably brew it differently. I'll try it again after I get more used to Japanese tea...
The second best (for me) would probably be #4, although #3 came very close. I preferred the first brew of #3, but the second and third brews were better with #4. And I like how the taste changes with #4, it seems more complex. But, #1 was a step better...
So, now I know I like sencha and approximately what I need to look for taste-wise. Hmmm, so much testing ahead of me...
Thanks again to Chip and the participating suppliers of tea!