On the top shelf of the chest freezer in Petra Sloane's flat in Edinburgh, there are two glass quart jars labeled in masking tape. CHICKEN, NOV 2025. BEEF, FEB 2026. Beside them, a row of small plastic deli containers, each holding about a cup of stock, also labeled and dated. The system has been running, in various forms, since 2018.
The argument for keeping homemade stock on hand is not a romantic one. Petra does not make stock because she enjoys the ritual, though she does. She makes stock because it makes weeknight cooking easier and her food taste better, and because the alternative, which is a carton of supermarket stock or a bouillon cube, is in her assessment not very good.
She is not a purist about it. There is a small jar of Better Than Bouillon chicken paste in her refrigerator for emergencies. It is fine. It is also visibly worse than her own chicken stock for any application where the stock is the point.
The economics of homemade stock are simple. A roast chicken carcass that would otherwise go in the bin produces, with three hours of low simmering, about two quarts of stock. The marginal cost is the cost of an onion, a carrot, and a stalk of celery. The marginal effort is putting things in a pot and putting the pot on the back burner.
The economics of homemade beef stock are slightly less generous. Beef bones cost money. Petra buys them from a butcher named Calum Ross who keeps a bag of marrow and knuckle bones in the freezer for her at about three pounds a kilo. She makes a batch of beef stock once every two months or so, usually on a Saturday when she will be home all day.
Here is the working rhythm.
Chicken stock. Whenever Petra roasts a whole chicken, which is about every two weeks in winter and slightly less in summer, the carcass goes straight into a pot with cold water to cover. A halved onion, a carrot in two pieces, a stalk of celery with its leaves, a bay leaf, a few peppercorns, and a sprig of parsley if there is any. No salt. Brought slowly to a bare simmer. Cooked at the barest simmer, with the lid slightly ajar, for two and a half to three hours. Strained through a fine mesh sieve into a large bowl. Cooled on the counter for an hour. Refrigerated overnight. The fat that solidifies on top is removed in the morning and saved separately. The stock is portioned into a quart jar for the freezer and four deli containers for nearer use.
Beef stock. Two kilos of mixed beef bones, including some marrow and some knuckle, roasted in a hot oven for forty-five minutes until well browned. Transferred to a large pot with cold water to cover. The roasting pan deglazed with a cup of red wine and the deglazing liquid added to the pot. A roughly chopped onion, two carrots, two stalks of celery, a head of garlic halved across the equator, a bay leaf, a few peppercorns, a sprig of thyme. Brought slowly to a bare simmer. Cooked at the barest simmer, lid ajar, for six to eight hours. Strained. Cooled. Refrigerated overnight. The fat removed. The stock reduced by half on the stove the next day to make a more concentrated product that takes up less freezer space.
Vegetable stock. Petra does not make a standing batch of vegetable stock. Instead, she keeps a bag in the freezer for vegetable scraps. Onion skins, carrot tops, celery leaves, leek greens, parsley stems, mushroom stems. When the bag is full she makes a stock from its contents with a few aromatics added. The stock is good for risottos and for vegetarian soups.
Fish stock. Petra makes fish stock about four times a year, usually when she has the heads and frames from a couple of whole fish her butcher orders for her. The fish stock cooks for only forty-five minutes. Any longer and it turns bitter. She uses it for chowders and for a Provençal-style fish soup she makes in winter.
What the stock replaces, in practical terms, is the carton or the cube. The carton of supermarket chicken stock costs about two pounds for 500 ml. It tastes faintly of celery and chicken and a great deal of salt. The cube tastes of MSG and dehydrated yeast extract.
Petra's chicken stock costs almost nothing, tastes of chicken, and contains no added salt, which means she can season the finished dish without worrying about over-salting. The last point is the practical one. A risotto made with home stock and a risotto made with carton stock will taste very different even if the rest of the recipe is identical, because the salt levels are not comparable and the seasoning of the carton stock pre-empts the seasoning of the dish.
The deli containers are the working stock. They hold about a cup each, which is the right amount for a small pot of soup, a risotto for two, a pan sauce for four. Petra keeps eight to twelve of them in the freezer at any given time. She thaws them overnight in the refrigerator or, more often, drops the frozen block straight into a hot pot where it melts in a few minutes.
The quart jars are the reserve. They hold the larger batches and get pulled out for bigger projects. A pot of beans cooked in chicken stock for Sunday dinner. A beef stew that needs a quart of reduced beef stock. A French onion soup for a cold January evening.
There are a few small principles that have emerged over eight years of doing this.
Never boil the stock. A bare simmer is the right temperature. Boiling turns the stock cloudy and dulls the flavor.
Skim the foam in the first half hour. After that the foam is mostly gone and skimming becomes a nervous habit.
Do not salt the stock. The stock will be used in dishes that have their own salt, and salting the stock removes a degree of control from the finished dish.
Do not over-vegetable the stock. Too many vegetables, especially carrot and celery, will make the stock taste like soup base rather than like the meat. Petra learned this the hard way in 2019 with a batch of beef stock that contained four carrots and tasted faintly of cake.
Cool the stock quickly. Petra puts the strained stock in a wide bowl in a sink of cold water for thirty minutes before refrigerating. The slow cool encourages bacterial growth. The faster the cool, the safer the stock.
Label everything. The masking tape and a permanent marker are the most important tools in the stock system. Unlabeled jars become mystery jars become wasted stock.
The two quart jars in the freezer, as of mid-June 2026, will be used by the end of July. The deli containers turn over faster, sometimes twice in a week. The vegetable scrap bag is currently about half full. The next chicken stock will probably happen on June 23rd, the day after Petra plans to roast a chicken for her partner's birthday.
It is not a hobby. It is a small piece of infrastructure. The stock jar earns its keep by being there when the cooking needs it, which is most of the time, which is the whole argument.
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