Kryddersild

Ingredients

Equipment Needed

• •Clean glass jar with a tight-fitting lid, 1 litre capacity
• •Small saucepan
• •Sharp knife and cutting board
• •Fine sieve or slotted spoon for serving

Instructions

1. 1

   Soak the saltsild

   Place the salt-cured herring fillets in a bowl of cold water and leave them in the fridge for six hours, or overnight if that's easier. Change the water once if you remember. Saltsild has been preserved in heavy salt for months, and if you skip this step the kryddersild will be too salty to eat. What you're doing here is drawing the salt back out of the flesh so the spiced brine has somewhere to go.

   Taste a small corner of one fillet after soaking. It should taste like pleasantly seasoned fish, not like seawater. If it still stings, soak for another hour or two.
2. 2

   Make the spiced brine

   Combine the water, vinegar, and sugar in a small saucepan. Add the allspice berries, cloves, bay leaves, peppercorns, and mustard seeds. Bring it to a gentle simmer, stirring until the sugar has completely dissolved. Once it's clear, take it off the heat and let it stand for ten minutes. The spices release their oils slowly, and that short rest is where the brine gets its depth.

3. 3

   Cool the brine completely

   This is the step you must not rush. Set the brine aside and let it cool to room temperature, then chill it in the fridge until it's properly cold. Pouring hot or warm brine onto fish will partially cook the flesh and turn the texture chalky. Cold brine on cold fish is the rule. The spices stay in the liquid the whole time; they keep infusing as it cools.

4. 4

   Cut and drain the herring

   Drain the soaked fillets and pat them very dry with kitchen paper. Lay them flat on a board and cut each one into pieces about three centimetres wide, roughly bite-sized. Traditionally these are served in pieces you can lift onto the bread with a fork, not whole fillets. Cut on a slight diagonal for a cleaner edge.

5. 5

   Layer the jar

   Take a clean glass jar of about one litre capacity and start layering. A few pieces of herring, a scatter of red onion rings, a couple of carrot coins if using, then more herring. Keep going until everything is in, pressing down gently as you go. Use glass, never metal. Vinegar reacts with metal and the whole batch will taste wrong.

   Sterilise the jar first by rinsing it with just-boiled water and letting it drain dry. You're not canning, but a clean jar means the herring keeps longer.
6. 6

   Pour and seal

   Pour the cold spiced brine over the layered herring, including all the whole spices from the pan. Every piece of fish needs to be fully submerged. If the top pieces are poking out, press them down with a small clean weight or top up with a little more cold vinegar. Seal the jar and place it in the fridge.

7. 7

   Wait

   This is the real work. A minimum of seven days, two weeks is better, three weeks is how it was done in houses that started their jar in November for julefrokost in December. The joy of waiting is not a figure of speech here. Every day the fish goes a little darker, the brine goes a little rounder, and the spices settle into the flesh. You'll know when it's right because the herring no longer tastes of vinegar and sugar separately. It tastes of one thing, warm and deep and faintly sweet.

8. 8

   Assemble the smorrebrod

   When you're ready to serve, butter each slice of rugbrod lightly if you like, or leave it plain. Lay three or four pieces of kryddersild across the bread, slightly overlapping. Spoon a generous dollop of cold sour cream beside the fish, never on top; the contrast is the whole point. Arrange the paper-thin raw red onion rings over the top. Scatter the whole capers. Finish with a few fronds of fresh dill. Serve at once with a cold beer or a small glass of aquavit, and let it be the first piece at the table. Tak for mad.

Chef Tips

• •The hardest part of this recipe is sourcing good saltsild. Ask at a Nordic deli, a Polish or Russian shop, or a fishmonger who knows what you mean. Pre-pickled herring from a jar is not the same thing and cannot be substituted; it's already been through its second stage and will turn to mush in the spiced brine.
• •Use clear white vinegar, not wine vinegar or cider vinegar. The Danish tradition is klar eddike, and the reason is clarity of flavor. You want the spices to come through, not the character of the vinegar.
• •The brine gets better the longer it sits. A jar made in late November for Christmas lunch is at its peak somewhere between two and three weeks in. After that it holds steady for another month in the fridge, so don't worry about making it too early.
• •The classic drink alongside is a cold pilsner with a small glass of aquavit beside it, ideally one flavored with dill or caraway. The spices in the fish and the herbs in the aquavit are cousins; they belong together.
• •Serve kryddersild as the first piece at any proper Danish lunch. Herring always goes first. Then other fish, then meat, then cheese. The order is the grammar of the meal, and it matters even at home.

Advance Preparation

• •Kryddersild must cure for at least seven days before it's ready to eat. Two weeks is better, three is traditional. Plan backwards from when you want to serve it and start the jar accordingly. For a Christmas lunch in mid-December, begin in late November.
• •The soaking of the saltsild takes six hours or overnight. Do this the day before you make the brine, or in the morning so the brine goes on in the afternoon.
• •Once cured, the jar keeps for up to six weeks in the fridge, fully submerged in its brine. Always lift pieces out with a clean fork so you don't introduce bacteria into the jar.
• •The raw red onion and sour cream for serving are last-minute. Slice the onion just before assembling so the rings stay crisp and bright.

Frequently Asked Questions

Nutrition Information

1 serving (about 150g)