Your article for acidic compost
In the article I link to below, it says to use coffee grounds. Since spent coffee grounds have a pH of about 6.9, I assume we are supposed to use fresh coffee grounds. Am I correct? Thank you in advance. https://www.gardeningknowhow.com/composting/basics/ericaceous-compost-info.htm
Certified GKH Gardening Expert
Quoting the article linked below.
"Many people feel that coffee grounds lower the pH (or raise the acid level) of soil, which is good for acid loving plants. But this is only true for unwashed coffee grounds. If you rinse your used coffee grounds, they will have a near neutral pH of 6.5 and will not affect the acid levels of the soil".
To be honest there is not as much material out about un-washed or un-used coffee grounds.
Probably due to people actually using most of the coffee they purchase.
Coffee grounds are high in nitrogen and mixed with leaves can make a very good quality compost.
5 to 10 pounds of used grounds mixed into four cubic feet of leaves is a good ratio. Fresh grounds will likely preform very much the same, exposed to moisture.