To me, elderflower cordial is the essence of early summer, distilled. Every year there's the patient wait until the elderflowers look just right, the trip spent snipping and stashing blooms in a bag, and then the careful process of making the cordial.
My mum's recipe is simple and elegant, and it results in a nearly magical flavor, especially when it's homemade. When she was little, my mum was told to only pick elderflowers on a sunny day; I'm pretty sure that's not necessary, but I follow the rule regardless.
It is important to pick your elderflowers away from the road so that the fumes from cars and trucks haven't settled on them; you can't wash the flowers, as they will lose their pollen. Choose flowers that are in full bloom: You want a big froth of creamy five-petalled flowers that haven't started to go brown. Snip the flowers off near the top of the stem -- you don't need any leaves. Their season usually runs from late May to June, with a bit of variation depending on climate (in the Swiss Alps, for example, the flowers bloom later than they do in the UK.)
More: Looking for another way to eat your flora? Try arugula flowers in your next salad.
In addition to the flowers, you'll need a couple of other items to make the cordial. You can buy the food-grade citric acid online (in my mum's day, they'd stock it at the pharmacy, but no longer), and you can find a square of muslin for straining the cordial at your supermarket. To drink the cordial, I like to dilute it with cold sparkling water, though some people prefer to use still. Either way, you only need a splash of cordial in each glass -- the result is sweet but strong.
25 heads (each made up of several clusters of flowers on one stem)of elderflower 1 lemon 1.2 kilograms (5 cups) white sugar 1 liter (4 cups) water 50 grams (1/4 cup) citric acid
Collect the elderflower heads. Shake them lightly to remove any bugs, then place them into a big mixing bowl. Peel the rind off the lemon in thick strips then cut it into quarters and add it all to the bowl.
In a big pan, combine the sugar and the water. Place the pan over a medium heat and stir the mixture occasionally until all of the crystals have dissolved. Take the pan off the heat and stir in the citric acid. Leave it to cool until it's lukewarm.
When the syrup has cooled, pour it into the bowl. There should be enough liquid to cover the flowers and the lemon, though a few bits may bob to the top. Cover with cling film and leave at room temperature overnight.
The next day, line a colander or deep sieve with muslin and set it into a big bowl or pan. Pour the contents of the elderflower bowl into the muslin, taking care that it doesn't overflow.
Place a couple of clean glass cordial bottles in an oven set to 210° F (100° C) until they've been heated through. Let the bottles cool for a bit -- they can be warm, but not hot. Use a jug and a funnel to pour the cordial into the bottles. It will keep in the fridge for up to a month.
If you want to freeze the cordial, wash a plastic bottle (do not heat it in the oven) and funnel the cordial into it. (I typically use two glass bottles and 1 plastic bottle when I make a batch of the cordial.) The cordial will keep in the freezer for a few months.