I’m thinking of a gloomy grey Sunday. Rain pattering on the skylights in the kitchen. The Viburnum outside the window scratching back and forth. The distant rumble of the motorway carrying on the wind. It was the last day of the Christmas holidays, the eve of work beginning again. It felt like a good day to put a roast on the table.

For me, a Sunday roast means dinner, not lunch – prepared in the afternoon and eaten about 6 or 7pm. That was how it always was at home. Sunday afternoons meant mum in the kitchen, making dinner. Gran peeling vegetables and doing the ironing. Dad would probably be in the garden, or engaged in some DIY task. The veg would be peeled and put into a dish of water. The main might be roast chicken, often done in my mum’s old enamel roasting tin, which had a lid with dimples on. It could be roast beef, with slivers of garlic studded into the meat. A leg of lamb was my mum’s favourite, served with jellied mint sauce. But I think it’s the smell of roasting chicken that’s the most evocative. The scent of crisping skin and sizzling fat permeating the kitchen. Steam from the vegetables fogging the windows.

When I roast a chicken, I have a few different approaches I use, none of them very complicated. I might follow Laurie Colwin and sprinkle the top with paprika. I might scent it with a pierced lemon, approximating Marcella Hazan or Nigella Lawson. Or I might use herbs and onion in the cavity. But always, I will sprinkle the whole thing inside and out with salt. And if possible, I’ll do this a few hours before putting it into the oven.

Judy Rodgers’ ‘Zuni Cafe Cookbook’ is probably the best expression of salting a chicken in advance. Her roast chicken bread salad is hard to beat, but it does require a small chicken, and salting a good two days ahead. But why salt in advance at all?

Behind the recipe: salting meat

Recipes for roasting or braising meat often ask you to add salt to it some way in advance of cooking. This might be in the form of a rub or marinade, or just a sprinkling on the surface either a little or a lot of time before it goes into the oven or pot. What is the point of doing this, and is there any advantage to doing it a long way in advance?

Cookbooks will often describe salting in advance ‘to draw out the juices’, especially from cuts like steak and chops. Yes, salting will do this, through a relatively simple process of osmosis, where the concentrated salt on the outside persuades water to come out of the meat cells to dilute it, making the salt concentration more similar to that on the inside of the cells. However, this isn’t the only thing that happens.

As water is drawn out, salt is drawn in, to balance the concentrations. This extra salt inside the meat attacks some of the proteins, breaking them up, and making the solution of salt + protein in the meat more concentrated than the now more dilute brine on the outside.

So now the operation works in reverse, drawing water back in from the outside. So we have both salt and water being drawn into the meat. This doesn’t really change the weight of the meat – the juices being drawn back in came out of it in the first place, and not all of them will go back. But now extra salt has been added to the meat, and the proteins have also been damaged a bit, making the meat a bit more tender, and also less able to squeeze out juices during cooking, as the proteins cook and contract.

Osmosis is not a very fast process, so the further in advance you add the salt, the more likely this is to happen and to penetrate deeper into the meat. Do it too far ahead, or with too much salt and the meat will become overly salty and unpleasant, or the proteins will become too damaged and be dry when cooked.

When it comes to roast chicken (and also to other cuts with the skin, such as pork with crackling) the other benefit is in drying and seasoning the skin. By helping to create a dry surface to the skin, it makes it easier to get the surface temperature hot enough to crisp the skin. When there is water there, the temperature is limited to around 100C, but as soon as all the water is driven off, where there is fat in or under the skin, the temperature can go up and up, which allows the skin to crisp and crackle.

Further reading:

Serious Eats: the truth about brining turkey and the burger lab: salting ground beef

The Zuni Cafe Cookbook – containing Judy Rodgers’ recipe for roast chicken, and lots of other discussion about brining and salting meat in advance.

Smitten Kitchen has also written about the Zuni chicken.