Nice tarp setup, hope it helps.

By "burn the berries", I assume you mean the UV white drupelet damage. This occurs on TC berries here to some degree even during cloudy, cool weather--the UV still penetrates.

High temperature so far this year is 88--and that was back in May.

My latest thinking on UV damage is that the sun angle is more important than the temperature, that is why late-season berries do not turn as white even in heat.

Yes, I mean the white, hard druplets. And you're right, even during this summer my TCs have suffered from this, but not so much that I needed to do anything about it.
I consider TC a late season berry. Are you saying the early August sun at 95F won't be a problem? I think it is. But I will pay close attention to the spots along the top on the north side where there isn't any coverage.

Early August 95F will likely produce more white drupelets, but not as many as July 4th 85F. I have noticed over the years that 90+ September heat does not affect the later berries.

Sun angle is decreasing rapidly after Aug 1; it is the same angle as mid-May.

Today was my peak TC harvest: 18 pounds from 20 feet of trellis. One or two white drupelets on each of 1/4 of the berries, the other 3/4 are clear. All black satins and black diamonds are clear.

That's interesting about the sun angle having such a significant effect. It explains why I had white druplets so bad this year with my TCs being a month early. I tried using burlap to shade them, but it just blew off in a wind storm. Then 1000's of yellow jackets found my ripe berries...

The sun angle thing is interesting, but I have to report that our sudden 102 degrees of Saturday whitened nearly all of my red phase thru black but unripe phase TCs and Black Satins.

Green/partial red phase and fully ripe berries were unaffected.

Lots of UV at 102 sunny degrees regardless of the angle.

This is interesting because my TC blackberries had their best year ever. I gave them plenty of water, but they were in covered in 4 100+ degrees days, and many 95+ days.

Now, my raspberries and blueberries could have used the shade cloth!

102ð TC UV/heat damage, south-facing, plump ripe berries undamaged.

{{gwi:123610}}

Happy to report that the shade did a marvelous job of preventing any berry damage. Except a few around the edges and high up on the north side. My freezer is full of blackberries.
My next door neighbor's Navaho blackberries were mostly ruined. Got hit at the worst time. I put the shade back up today for 95 degree afternoon. We might hit 100 later in the week.

Thanks for the follow-up report. My multiple, closely-spaced rows are harder to protect than your single row, but I may eventually get some system going.

The post-heat picking here was 13 pounds usable (juice), 17 pounds junk berries.

I have a couple of different varieties of thornless blackberries. I grow them in a place that is mostly in shade. It gets half day sun only in June-August. It is very productive. I don't think they need to be in full sun here in PNW. I don't shade, don't irrigate, get lots of berries and they are covering previously unused land.
John S
PDX OR

What do you guys think of Black Satin? You rate its flavor highly?

Here in zone 7B we are doing great. This year we had a big crop I love blackberry the only thing I hate about it is the thornes.

Black satin is best for cooking, not fresh eating. The cooked flavor is very good.