Hi,
2 years ago I tried following an 18th century recipe for pickling ash keys but I caught the keys too late, and they were as tough as nails - even after simmering for ages in plenty of changes of water (to remove bitterness). Hours in fact.
Last year, local ash trees produces virtually no 'keys'.
This year I had almost forgotten about ash keys but then found a bunch in my face as I was foraging the hedgerows of Cornwall (1st wk june). So I picked many bunches of keys in ernest for pickling...
Point 1. For the pre-pickling process, as far as I am concerned... There must be no bulging of the main seed embryo. All you are looking for is the FLAT undeveloped key.
Point 2. To check potential edibility bite a key or two in a bunch. If they snap cleanly between your teeth they are candidates for pickling. If they 'take a tug' between your teeth to incise, then forget them.
The next step is to boil in several changes of water, and then drop into pickling vinegar.
They do not have the flavour of capers or anything similar, and to be perfectly honest are a novelty rather than a serious food pickle as far as I am concerned. However, there are a few wheezes which I am working on that may produce unexpected results which I hope to put on-line in the future, as well as some fotos of what the pickled items look like.
M