Javacat wrote:I stumbled upon a great way to preheat portafilter baskets the other day by using an electric ceramic cup warmer or a candle warmer. All you do is put your basket or stack multiple baskets on the warmer and whala, your baskets are hot and dry ready to go. Some of the warmers can get quite hot so be careful, but the heat can be reduced by placing a small towel over the top. Another use is as a tamper warmer - no more icy tamper first thing in the morning.

HB wrote:Years ago I did measure the temperature difference between the top and bottom of the puck for hot/cold baskets:



The distance between the lines indicates the cold/hot basket delta; the distance from the 0 axis represents the top/bottom delta. It shows that indeed cold/hot baskets do have a measurable effect on the first seconds of the delta between the top/bottom, but the effect falls below the boiler's natural temperature variance shortly thereafter (measured on a La Marzocco Linea without PID controller). That said, I don't consider the above chart the last word on the matter, as it was hastily created from just a few trials back in 2004 in response to a discussion on CoffeeGeek.