dfk41 I donāt think so, youāre just leaving them to steep as long as you can to get the most out of them, before too cool to enjoy.
Iād grind medium drip, 55-60 on a Niche as a guesstimate. I can give a brew a go over the weekend if you like.
More soluble beans (to me that means Colombia, Kenya, Rwanda, Peru, Ethiopia, Burundi) work best, if roasting them darker does that for other origins, then fine (I never buy dark roasts, but roasts I bought as being light and arrived darker than Iād ever drink didnāt exibit higher solubility).
For darker roasts I tended to back off the brew ratio a bit to 1:20, but if you like it more intense you might not bother.
Some lighter, less soluble beans (Guatemala, Cost Rica, Brazil) might struggle, but otherwise itās pretty forgiving overall.