The secret to this marmalade is dilution: you have to thin out the potent bergamot flavor until it's palatable. The amount of water called for, 10 cups, is not a misprint. Even so, the finished marmalade is still potent. The faint-hearted may want to remove some portion of the peel in step 1.
Note that this is a three-day process, necessary to extract the maximum pectin from the pith and seeds.
2 pounds fresh bergamot
10 cups water
3 1/2 pounds sugar (7 heaping cups)
1) Scrub the fruit well in cold water. Storebought citrus will likely be waxed, so wash it again in very hot water to remove the wax. Using a vegetable peeler or paring knife, remove the outermost layer of fragrant zest in long strips. Finely cut the peels crosswise into the thinnest possible shred, ABOVE. Place the shredded peel in a large, non-reactive bowl. (If you want a less potent marmalade, discard 1/3 to 1/2 of the peel, or set it aside to use for bergamot syrup.)
2) Quarter the peeled fruit. Remove the seeds and reserve them in a small dish. Using your sharpest knife, slice the quarters cross-wise as thinly as possible, BELOW. Add the shredded pulp to the bowl with the peel.
3) Add one cup of water to the dish with the seeds. Cover the shredded peel and pulp with the remaining 9 cups. Cover both containers and refrigerate overnight.
4) On day 2: The seeds will have released a clear pectin jelly. Collect it by straining the contents of the dish through a fine-mesh sieve over a bowl, rubbing the pectin jelly through the sieve. Discard the seeds. Put the peels, pulp, and their soaking liquid into a large pot, and add the pectin stock. Bring to a boil over high heat, and boil hard for 10 minutes. Remove from the heat. Once cool, cover and refrigerate overnight.
5) One day 3: Spread the sugar on a baking sheet and warm it for 15 minutes in a 250-degree oven. Pour the peels and their soaking liquid in a wide preserving pan. (The mixture should be no more than 1 1/2 inches deep in the preserving pan.) Bring to a boil over high heat and boil hard for 5 minutes, then stir in the warm sugar to dissolve. Reduce the fruit-sugar mixture over high heat, stirring regularly, to the gel set, about 20-25 minutes. You know you're getting close when mats of large bubbles, which I call "frog eyes," cover the surface of the hot marmalade and threaten to boil over. To test for a gel set: put 1 teaspoon of hot marmalade on a chilled saucer and place in the freezer for 1 minute. If the puddle of marmalade has formed a "skin" that wrinkles when you push your finger through it, then you have a gel set. If not, if the puddle is still syrup, then bring the preserving pan back to a boil and cook for another minute or two. Don't overcook the marmalade.
6) At the gel set, ladle the hot marmalade into 10 prepared half-pint jars, leaving 1/4 inch headspace. Stir the cooling marmalade frequently as you fill the jars, and take care that the peels and jelly are distributed equally. Seal the jars, and process in a boiling-water bath for 10 minutes.
Yields 5 pints