just a note
I have found reference to (and sources for!) something called dibbs, or vino cotto, as a sort of grape molasses, which looks to be similar.
This is the time to contact wineries in your area and ask for it, it’s not terribly shelf stable, so secure a supply now.
on Verjus variants;
Unripe apples, grapes, and pears are abundant, you may be able to get a nice supply for making sour juices
this is also a good time to get elderflowers or bag the heads of the plant to protect them from birds, so as to get the fruits.
many period recipes call for a good blanching before cooking. This makes a lot of sense when there are no pesticides. If you are using garden or organic produce, you may wish to blanch them to remove any “passengers” before they hit the plate.
this is a great time to decide if and how you will be preserving things toward the future; fermented and pickled foods were a large part of the historic diet, and vegetables will be in perfect condition for preserving over the next two to three months.
on sumac; if you wish to use sumac as a seasoning, watch for roadside plants and choose those from alongside fields and streambeds rather than roads and golf courses. They aren’t ripe yet, but knowing where they are makes it easier to schedule grabbing them. One good “candle” or cluster of berries is usually a good 4 ounces of seasoning.