To appreciate the unique flavour of fresh berries, they must be used right away when enjoyed raw or just slightly cooked, as in cordials, or baked whole in pie crusts. To avoid overindulgence, however, a part of the crop might be destined to make preserves, and it could become a chore to cook and process the fruit right after harvest, when the weather is hot.
In these cases, a helpful technique that may be applied to berries and a variety of other fruits, is to freeze in airtight bags until the weather cools down. I always wash and blot the fruit dry before packing it as flat as possible in a sealable bag. Then, I insert a straw in the bag and close the seal around the straw, while gently pressing the bag; the straw serves as a canal to remove as much air as possible. Finally, I remove the straw and finish closing the seal. I had a couple of bags of blackcurrants in the freezer from last summer (one seen in the photo), and finally got around to make a batch of jam. There is no need to thaw them, just cook them for a few extra minutes.
Blackcurrant Jam – Mermelada de Grosella Negra
Ingredients (for approximately four cups of jam)
4 cups blackcurrants, washed (fresh or frozen)
1 cup water
2 ½ cups granulated sugar
1 tbsp lemon juice
Place berries and water in a pot over medium heat (photo below, left); bring to a boil and cook for 10 minutes (15 if from frozen), stirring constantly until fruit softens and begins to break (photo below, right):
Add sugar, stirring to incorporate (photo below, left), then add lemon juice (photo below, right):
Continue cooking and stirring, and start timing from this point on. For the jam to set, the gel point (around 220°F, or 105°C, at sea level) must be reached; this is slightly above the boiling point of water, so that means that the mix needs to cook until enough water has either bonded with sugar molecules or evaporated, for the temperature to go above its boiling point (check the Serious Eats Jam 101 for full explanation of the process). I do not have a candy thermometer, and just looking at the hot mix will not determine if it will set once it cools down, so I use the trick of placing a couple of metal spoons and a saucer in the freezer, and test the mix every five minutes by dipping a cold spoon in the mix and placing it back on the saucer and in the freezer for one minute. The mix cools fast and will adhere to the spoon if it has set, or will run more like a thin sauce if it has not set. In the photo below, left, the cold mix on the test spoon is still runny after cooking for 10 minutes. After cooking and stirring for another 5 minutes, the hot mix looks runny (photo below, centre), but when the cold spoon test is done, the mix adhered and formed a thick layer on the test spoon (photo below, right):
The jam is ready! If the jam is going to be consumed within a few weeks, just transfer the hot mix to clean glass bottles with lid, let cool, and keep in the refrigerator. If the jam needs to be stored for several months or is to be sold or given away as gifts, then it must be transferred to sterilized Mason jars with new lids to be processed in a bath of boiling water for 10 minutes.
I wanted to give a couple of the jars to friends, so I decided to process them. I placed several one-cup Mason jars in my water-bath pot fitted with a metal basket, and covered with tap water (photo below, left); I brought the water to boil over high heat, and let the jars in the bath for one minute (photo below, right:
I turned off the heat and removed each jar, filled with water from the bath (photo below, left); this is done because I will be processing jars filled with jam later on, so that water must be displaced from the bath. I poured the hot water from each jar into a small pan (photo below, right):
The rim rings are sanitized by immersing in the boiling water for a few seconds; I used a tool with a long handle to sanitize all the rings at the same time (photo below, left). The lids must not be boiled when their seals are exposed, because they might be damaged, so I dipped them in the reserved water (hot but not boiling), and removed them after a few seconds (photo below, right):
The rest of the utensils are also dipped in the hot bath, to sanitize. In the photo below, from top to bottom, from left to right: lids with seal; Mason jar funnel, rim rings; Mason jar and tongs; large spoon (or ladle); and metal spatula:
To fill the jars: place funnel on one jar; scoop hot jam with the spoon or ladle onto the funnel, and fill the jar leaving a 1/2 inch spacing from the rim (photo below, left); transfer the funnel to the next jar, then slowly run the spatula across the jam to release air bubbles (photo below, right):
Wipe any jam from the jar’s rim with a paper towel, then place a lid on top; I used a small magnet to pick up a lid without touching the side with the seal (photo below left). Screw one rim ring, just until it feels tight; do not over do it. Repeat with the rest of the jam and jars. Place the jars in the water bath, making sure they are completely covered with water, and bring water back to boil over high heat (photo below, right):
Cover the pot and let boil for ten minutes. Turn off the heat, let rest for a couple of minutes, and then remove the jars using the tongs, very carefully not to shake them excessively. Place on a kitchen towel and leave completely undisturbed until they reach room temperature (overnight is the best). Once cool, the jars may be labelled. Before storing, check the seal of each jar by pressing the centre of the lid, which should not pop or move at all; if it does, the seal is not good. These jars may be stored in the fridge for several weeks. The jars with proper seal may be stored in a cool dark place for at least one year. In the photo below, the batch from my 2018 harvest, freshly prepared a couple of weeks ago:
If a dedicated hot-water bath kit is not available, a large pot may be used, but a metal grid has to be outfitted to be placed inside the pot, making sure that the jars do not touch the bottom of the pot. The pot must be large enough to house the jars without touching each other, and enough water to completely cover them.
I have found that it is not a good idea to cook extremely large batches of fruit, because the cooking times become too long, and the temperature will often not rise enough to reach the gel point. Six cups seems to be the empirical maximum for success for me, with a cooking time (after adding sugar and juice) of approximately 18 minutes, for blackcurrant jam of medium thickness.
FUN FACT: Both the Spanish word mermelada and the English word “marmalade” come from the Portuguese word marmelada, which means “quince jam” (from marmelo – quince). Quince was one of the first fruits to be recognized as suitable to prepare thick spreads, due to its high pectin content. Nowadays, many fruits other than quince are used to make spreads; in Spanish, the name translated as any jam or jelly (as in “fruit spread”, not gelatine; that’s a different story) but curiously, in English it is only applied to citrus fruit spreads.
In Mexico, blackcurrant jam would be a fancy treat, but others such as the humble mermelada de fresa (strawberry jam), tropical de piña (pineapple) and citrusy de naranja (orange) are everyday staples to spread on toast, or used to fill sweet baked confections.
I am joining Fiesta Friday #263 and I have already spotted a few recipes that could incorporate my blackcurrant jam as a topping or sweet addition. This week Angie @ Fiesta Friday is hosting by herself, and there will be an opportunity for anyone and everyone to vote for their favourite recipes, starting on Tuesday at 12:00 pm EST.