Ketchup-based BBQ Sauce

Ingredients

• 2/3 cup ketchup
• 1/2 cup apple cider vinegar
• 1/4 cup rub

Method

Combine the ketchup, apple cider vinegar, and rub in a small saucepan. The vinegar is doing two jobs here: it sharpens the ketchup's tomato sweetness and acts as a preservative, lowering the pH so the sauce keeps in a sealed jar for weeks. The rub — your spice backbone — needs gentle heat to bloom its aromatics and marry with the liquid, which is why you're not cold-mixing.

Set the heat to medium and bring the sauce to a proper simmer: small, steady bubbles breaking the surface every second or two, not a languid tremor. This is your simmering target. Once it's there, you're reducing the liquid slightly to concentrate flavour and thicken the body. Most of the work happens in the first three minutes — watch the surface. The sauce will darken slightly and the vinegar's sharp edge will soften as it mingles with the tomato and spices. Stir every 30 seconds or so to prevent the bottom catching and scorching, which introduces bitterness that no amount of sugar will mask.

After five minutes, the sauce should coat the back of a spoon lightly and pull away clean when you drag your finger through it. If it's still pouring like thin ketchup, give it another two minutes. The acid-in-cooking|acid will have integrated fully — you won't taste sharp vinegar in isolation anymore, just a rounded tang underneath the umami of the tomato and the warmth of your rub. Taste it now and adjust: too thin means more time on heat; too sharp means a pinch of caster sugar or honey to smooth the edges; too flat means you've underseasoned the rub itself.

Take it off the heat and let it settle for a minute before use. As a finishing-sauce, this works best brushed onto meat in the final few minutes of cooking — the sugars in the ketchup will catch and caramelize, building depth. If you're serving it as a condiment on the side, decant it into a clean jar once it's cooled. It'll thicken further as it cools thanks to the gelatin in the ketchup.