Tarragon Vinegar for Salad Dressings

A cold infusion that needs no cooking, only time and a well-washed jar. The proportions here are generous: a pint of loosely packed tarragon leaves to a pint of vinegar gives a strong, almost medicinal result that you will want to dilute into dressings rather than use straight.

• The vinegar to useWhite wine vinegar is the traditional base for tarragon and keeps the herb's anise note clean. Cider vinegar works; distilled white vinegar is sharp enough to flatten the tarragon, and malt vinegar will bury it entirely. Aim for something around 5 percent acidity, which is standard for bottled vinegar.
• Measuring the leavesA pint of tarragon leaves means volume, not weight — leaves stripped from the stems and dropped into a pint measure without packing, roughly 1 to 1.5 oz. Use French tarragon if you can get it; Russian tarragon is coarse and nearly flavourless.
• Keep everything submergedAny leaf sitting above the surface of the vinegar can spoil or grow mould. Press the herb down and top up with vinegar so it is fully covered, and use a glass jar with a plastic or coated lid, since vinegar corrodes bare metal.
• Bruise, don't chopCrushing the leaves lightly against the side of the jar releases more oil than leaving them whole, and it avoids the muddy, bruised-green taste that chopping produces.
• Two weeks, in the darkA cool cupboard is better than a windowsill; light fades both the colour and the aroma. Taste at ten days — if the tarragon reads clearly, strain then rather than waiting the full fortnight.
• StrainingPressing through a cloth extracts more, but it also pushes fine sediment into the bottle. Strain through a sieve first, then through damp muslin, and let it settle before you decant if you want a clear vinegar.
• Bottle and keep"Seal" here means a tight cork or cap, not heat processing — the acidity does the preserving. Stored cool and dark it holds its flavour six months to a year, though the aroma softens after the first few months.
• Yield and useAbout a pint. Reckon on one part tarragon vinegar to three parts oil in a vinaigrette, or use it as a fraction of the total vinegar in a mixed dressing; it is also commonly used in the reduction for a bearnaise.