Gadenin日本語Get the appThis is not a fruit you taste to test
The first thing to accept is that ripeness tests borrowed from other citrus do not apply here, because the flesh never becomes pleasant to eat. It is fiercely sour and genuinely bitter, with coarse, seedy, rather dry pulp, and no amount of extra time on the tree changes that. Anyone leaving the crop hanging in hope of sweetness is waiting for something that will not happen. What ripening does change is juice volume, acidity, peel aroma and the pectin in the pith, and those are what you are actually harvesting.
That means you pick according to what you intend to make, not according to a single date when the tree is ready. Marmalade wants fruit taken in the first winter after it colors, when the pith is thick and pectin is at its highest and the peel is aromatic and still firm. Juice for cooking and marinades wants slightly later fruit, when acidity has softened a fraction and volume is up. Peel and zest for drying can come from almost any colored fruit, since the oil in the flavedo is present throughout.
Judge the fruit by weight and skin rather than taste. A fruit ready for marmalade feels heavy for its size, has skin that has gone from hard and glossy to slightly yielding under thumb pressure, and gives a sharp burst of oil when you scratch it with a fingernail. A fruit that feels light and sounds hollow has dried inside, which happens to long-held fruit, and its juice is not worth collecting even if the peel is still excellent.
The fruit that colors, greens again, and colors a second time
Bitter orange does something that catches out almost every grower who meets it for the first time. A fruit reaches full orange through the first winter, exactly as you would expect. If you leave it hanging, it does not fall and it does not rot. Instead, as temperatures rise the following spring and summer, the rind re-greens, turning back to a dull green or greenish bronze, and it hangs on through that second season looking like an unripe fruit again. Then, as the next winter's cold arrives, the same fruit colors orange for a second time, and it can repeat this for two or three years before it finally drops.
The mechanism is straightforward once you know it. The orange color is what remains when cold weather breaks down the chlorophyll in the rind. Warmth in the following growing season lets the rind rebuild chlorophyll, and the green masks the orange pigments underneath, which never went anywhere. This is why the Japanese name daidai, meaning generations, was given to the tree: fruit from several years hangs together on the same branches, one generation above another. A tree in late winter can be carrying newly colored fruit, last year's re-colored fruit and the swelling remains of the year before, all at once.
Practically, this means green skin on a bitter orange tells you almost nothing on its own. A hard, small, glossy green fruit on this year's wood is genuinely immature. A large, heavy, slightly dull green fruit hanging on older wood in midsummer is a fully mature fruit that has simply re-greened, and it can be picked and used immediately. Tell them apart by size and by weight in the hand, and by tracing the fruit back to the age of the wood it is sitting on.
| What you see | What it actually is | What to do |
|---|---|---|
| Small hard glossy green fruit in summer, on new wood | This year's immature crop | Leave it; it will color in the coming winter |
| Full orange fruit in winter, firm and heavy | First-winter fruit at its best for marmalade | Pick now for the highest pectin and best peel |
| Large dull green fruit in summer, on older wood | Last winter's fruit that has re-greened | Fully usable; pick and juice it or leave for display |
| Orange fruit that feels light and sounds hollow | Fruit held too long that has dried inside | Use the peel only; the juice is not worth taking |
| Fruit with split or shriveled skin | Uneven watering, or an over-held fruit past its useful life | Remove and compost it |
How to pick without wrecking next year's wood
Never pull a bitter orange off the branch. The rind is thick and the attachment is strong, and a straight pull tears out a plug of peel or strips a length of bark from the fruiting spur. Both invite rot, and the torn fruit will not keep. Cut instead, with sharp snips, leaving a short stub of stalk no more than a quarter inch (5 mm) long. A long stalk left on a fruit will puncture the fruit next to it in the basket, which is how a crop that looked perfect on the tree develops mold within a week.
Pick when the fruit is dry, ideally in the morning after any dew has gone. Wet peel bruises more easily and any surface moisture carried into storage becomes mold. Handle the fruit as though it were a tomato even though it feels like a cricket ball, because rind bruises show up two weeks later as soft brown patches, and drop it gently into a shallow basket rather than a deep one.
Bear the thorns in mind at every stage. Bitter orange thorns will pierce a fruit as it comes past them and will certainly pierce a hand reaching into the canopy. Long-handled snips let you take fruit from inside the tree without pushing your arm through, and a thick sleeve is worth more than a glove, since most thorn wounds on citrus land on the forearm.
Pick the fruit you actually intend to process. Bitter orange peel and juice are strong-flavored and a very small tree produces more than most households use in a year. Leaving the surplus on the branch is an entirely legitimate choice, and it is what makes the tree ornamental through winter.
Keeping what you pick
Whole fruit keeps two to four weeks in a cool room and six to eight weeks refrigerated, provided it is dry, unbruised and not touching. Do not wash it first: the surface oils and waxes are the fruit's own protection, and washing removes them and pushes moisture into the stem scar. Check stored fruit weekly and take out anything soft, since one rotting bitter orange takes its neighbors with it in days.
For longer keeping, process rather than store. Juice freezes well in small portions and loses very little of its character, which suits a fruit you use a spoonful at a time. Peel dries readily: take the colored flavedo off in strips with a peeler, avoiding the white pith, and dry it in a warm airy place until it snaps rather than bends. Whole fruit halves and quarters can also be frozen for marmalade, and freezing actually makes the later extraction of pectin from the pith and seeds a little easier.
Keep the seeds and the pith when you make marmalade rather than discarding them. They hold most of the pectin in the fruit, and a bitter orange has a great deal of it, which is why this species has been the traditional marmalade fruit for centuries. Tied into a piece of cloth and simmered with the peel, they will set a preserve without any added pectin at all.
What to record at harvest
Write down the date the first fruit reached full color, the date you picked, the weight taken and what you made with it. Because this tree holds several years of fruit at once, the only way to keep track of what is on it is to record which branches or which side of the tree you cleared and when. Without that, you cannot tell held-over fruit from this year's crop by looking.
Note also how much you deliberately left hanging and what condition it was in when you finally removed it the following year or the year after. That record tells you, for your own climate and your own tree, how long fruit stays worth using before it dries out internally, and that number is far more useful than any general figure.