This evening, I made a big, wide, 6.75-quart Le Creuset potful of chili and used the diffuser for the first time. This post is not about the chili but about the diffuser and its behavior with the Le Creuset pot.
First, the size and shape of the diffuser were perfect for the pot, and my first concern was eliminated. Just a very small amount of the plate stuck out from beneath the pot. That meant more heat was focused on cooking and less heat escaped to the surrounding environment compared to the square plate and seemingly, even the round plate. On that second point, I'm not 100% sure.
Making the soffrito was a big surprise, as the pot heated up much more quickly than I thought it would. I got the soffrito started, turned to do some cleanup in the sink, and much quicker than expected I could hear that the pot needed attention. I stirred and turned the heat down, and kept a more attentive eye on the progress from then on. I can't say for sure, but it seemed that the pot was heating quicker than without the copper plate when it rested directly on the hob. Perhaps one day I'll run a test and know for sure.
Apart from heating quickly, the pot and contents seemed more responsive to changes in temperature. No "facts and figures" to share other than to say I've used that pot, on that hob, to make that same dish several times, and I could feel, or sense, a difference. In any case, I don't think anything was lost by having the plate between the pot and the hob.
The reason I got the diffuser was to even the heat on the bottom of the pot since the pot is wider than the hob and the heat at the edges of the pot was noticeably lower which affected the cooking performance. The diffuser solved that problem beautifully, and based on the bubbles in the chili, the heat was even across the entire bottom of the pot.
Nothing is perfect, however, and the one issue I encountered was a result of the quality of the Le Creuset and the diffuser plate. Unlike my older LC, the bottom of the newer pots are fully glazed. The surface is smooth and durable. Likewise, the diffuser is beautifully finished and is also very smooth. When there was just the soffrito in the pot, the pot would slide around on the diffuser, and care had to be taken to avoid that movement. Grabbing a handle with a towel helped, as did being quite deliberate in my stirring method. When the pot was fuller and weighed more, the sliding stopped and cooking could proceed in a more normal fashion. I have a very wide All-Clad pot (the other reason I wanted the diffuser) and it will be interesting to see how it behaves on the diffuser plate.
Overall, I am very happy with the decision to buy the plate even though it was somewhat spendy. Shipping and tax added about 30% to the selling price. I don't regret spending the money one bit.
I hope my experience and review are helpful.
Here's a link to the seller and manufacturer of the diffuser plate: https://www.ebay.com/str/swmetals
This is the pot used for this review: (eG-friendly Amazon.com link)
