How to turn unripe stone fruit into a brilliant Japanese condiment – recipe

The Guardian

4 hours ago

Umeboshi is a puckeringly sour and umami-rich Japanese condiment made with ume, an Asian plum that's closely related to the apricot. It's usually made with ripe but firm fruit, which aren't all that dissimilar to the under-ripe and slightly flavourless apricots and plums found in most UK supermarkets and which make a great British stand-in for ume.
Our global food system is a wondrous thing, but as a Slow Foodist, consultant and food systems thinker, I can't ignore the benefits of shorter food chains, from lower transport emissions and reduced waste to improved quality and flavour. Of course, food miles are only one piece of the emissions pie, but that doesn't mean they're inconsequential, and we ought to consider them alongside other contributory factors such as livestock production and deforestation.
Many fruits such as mangos, bananas and apricots continue to ripen after harvest, so these delicate climacteric fruits are usually picked hard and green, and ripened in climate-controlled rooms filled with natural ethylene gas. It's an ingenious process, but it can produce floury, tasteless fruit with fewer nutrients.
By comparison, local, seasonal fruits tend to be tastier and more nutritious, but if you're unlucky and end up with fruit that just won't ripen, you can either cook it or turn it into umeboshi, which is a fun fermentation project. Like most fermentation recipes, the essence of this one is very simple, yet it's still a scientific process that requires care and attention to detail. Everything needs to be very clean and sterilised with vinegar or alcohol. Also, due to their high sugar content, fruits such as plums, apricots and peaches are prone to mould during fermentatation, so keep your hands and utensils scrupulously clean. And make sure the fruit stays submerged in its brine, or 'plum vinegar', to help prevent mould forming; if at any stage specks of mould do appear, it's best to compost the entire batch. There are plenty of detailed umeboshi guides online if you'd like a more in-depth explanation.
Firm apricots, plums or peaches
A splash of white-wine or cider vinegar
18% sea salt – that is, 1kg fruit will need 180g saltA clean vessel with a lid
A weight – a plate, fermentation weight or bag of salt, say)
Soak the fruit in water with a generous splash of vinegar for a couple of hours. Using a toothpick or tweezers, remove the little stem from the fruit, taking care not to cut into the flesh itself, and save any bruised or blemished fruit for something else, because they're more likely to develop mould. Weigh the fruit, then measure out 18% of its total weight in sea salt (that is, 180g salt for every kilo of fruit). Wipe out a clean storage jar or fermentation pot with vinegar or alcohol, then start packing in the fruit in layers, scattering each layer with the salt. Put a small clean plate or fermentation weight on top, then weigh that down with a clean weight or a sealed bag of salt.
Leave to ferment in a cool place out of direct sunlight for four weeks. Over the first three to seven days, the juices will slowly draw out of the fruit and submerge it. Make sure the fruit remains submerged, but don't crush it down.
When hot weather is forecast, drain the fruit (save the brine for dressings), then lay it on a rack and dry in the sun for three to five days, until it shrinks and turns crinkly. Store the dried fruit in a clean, airtight jar. Traditionally, umeboshi is aged for one to three years, but to be on the safe side, aim to consume it within a month or so.