I'm using a Fellow Stag and a metal V60 with a fabric filter. I do a 1:16 ratio (16g of coffee and 256g of water). Generally I'll place the V60 on the Stag while it brings the water up to a boil in order to heat it up. Then I'll saturate the fabric filter with the hot water. I'll use 212F water, but after pouring the water over the grounds, my instant read thermometer will read 195F. It seems weird that despite doing everything in my power to preheat all the equipment, the water drops a lot in temperature as soon as it hits the grounds. Any tips to tackle this problem?
Plastic tends to be the best, imo. I don't even really worry to heavily about preheating when using my plastic v60. But if j. Brewing with my Stagg XF, I absolutely place the Stagg XF on top of my Stagg kettle as well while it gets up to temp.
Though the Stagg XF does have the benefit of being double walled stainless steel, so it does a great job of keeping temp.