Always start the day with a pour over through Chemex. I brew 500grms - 65 grams bloom for 30 secs, then another 65 grams, 125 grams at 1 min, 125 grams at 1 min 20-25 secs and a final 125 grams at 1 min 45 secs and aim to have full draw down around 3 mins 30 secs give or take. I always check new beans with a refractometer with a personal preference for brews in the 20-21% extraction yield range for lighter roasts.
Received wisdom is 93c brew temp or even higher for lighter roasts but decided to check brew temp through a few brews. Obviously, bloom pours are likely to be cooler but was surprised to find that slurry temp for is around 55c and doesn’t rise much for second pour (60 grams). It’s only when third and four pours does temp get up to 90c, so for first minute and a half, brewing is well under 90c. So I’ve begun adding water after initial bloom as quickly as possible to get slurry up to and above 90c. Results, and it’s early days, are encouraging - more brightness.