III. Ordinary Things Essay 19
One Stove, Six Dishes
A bottleneck, a balancing loop, and the real question of order
Six things to cook. One stove with four burners, of which one is good, one is broken, and one does something slightly different to the other two. You have about an hour. Somebody is going to be hungry, somebody else is going to be late, and the whole thing has to end with everything hot at the same time, which sounds like a detail and is in fact the entire problem.
Here is the thing nobody tells you about cooking for people. The recipes are not the hard part. The recipes are solved problems that other people have already solved, and they will tell you how long each thing takes and roughly what it needs. The hard part is that six of these things are competing for one stove, and that they have different lengths, and that some of them need you standing there and some of them do not, and that if you get the order wrong, everything is ready at a different time and the meal has a first course and a last course and no middle.
Cooking for a crowd is a scheduling problem wearing an apron. And once you see it that way, the interesting question stops being what to make and becomes what the order has to be, which is a question about the structure of the work rather than about the food.
Six things: a roast, a tray of vegetables, a pan of potatoes, a salad, a soup, and a cake. Two hours from now, everything goes on the table together. Somebody is doing the cooking.
Now watch the constraint. The stove is the constraint, but not in the way people usually think. The constraint is not the number of burners, because you can put four pans on four burners. The constraint is the attention of one pair of hands, and the fact that some of these six things need hands and some do not.
The roast needs the good burner, and it needs an hour, and it needs checking every fifteen minutes, and it does not need watching. The soup needs a burner, needs stirring occasionally, and can be on a low heat for a long time. The cake needs the oven, which is a separate constraint and is not the same constraint as the stove, and it needs twenty-five minutes. The vegetables need fifteen minutes in a hot oven, and they need to be cut first. The potatoes need the last twenty minutes or they go soft. The salad needs no heat at all, and it takes seven minutes, and it must be made last or it wilts.
Now the order. The cake goes in the oven first, because it has a fixed time and it can wait afterwards without harm. The roast goes on the good burner next, because it is the longest thing and everything else has to fit around it. While the roast is cooking, and while the oven is busy with the cake, the soup goes on the low burner and the vegetables get cut, and the salad gets washed and the dressing gets made. When the cake comes out, the oven goes to high heat and the vegetables go in. When the vegetables come out, the potatoes go on. And the salad gets made last, in the last seven minutes, while the potatoes are on.
Nobody needs to be told that the order matters. Everybody does it roughly like that already, without a word about constraint or critical path. What the picture adds is the reason, and the reason is worth having because it transfers: the order is not about which dish is nicest to start with. It is about which dish has the longest tail, which dish needs you, which dish can be left alone, and which dish can wait.
The stove and the hands
It is worth being precise about what the constraint is, because getting it wrong is the usual reason the plan fails.
People say the constraint is the stove. It is not, quite. The stove has four burners and it is the oven that is genuinely scarce, since most domestic ovens have one cavity and one temperature. The real constraint is the cook: one person, who cannot be in two places, whose attention is the scarce resource, and who is needed for the parts of each dish that need hands.
This distinction matters because it changes the plan. If the constraint were the burners, the answer would be to spread the work across them and use them all. If the constraint is attention, the answer is to ask which tasks need hands and to get them out of the way of the burners, so that the burners can be busy while the hands are elsewhere. The potatoes need hands for two minutes and then need nothing. That two minutes is the entire cost of the potatoes, and it can be spent while the roast is cooking.
Heat is a loop, and so is the oven
There is a system thinking idea hiding in the way you handle a pan, and it is worth pulling out because it changes how you cook.
A dish on a stove is a balancing loop. It is colder than the burner, so heat flows in, so it gets hotter, and when it reaches the temperature you want, you reduce the heat or move it or take it off, and it cools a bit, and you put it back. The loop has a target, and the correction is applied continuously, and the target is the thing you are actually managing. You are not following a time. You are managing a temperature.
And the delay in the loop is the reason you have to look at the pan, and the reason a recipe gives you times at all. A recipe time is a prediction of when the loop will have settled if the burner is at a certain heat and the pan is a certain thickness and the food is a certain thickness. Every one of those is a condition the recipe could not state, so the recipe states a time and asks you to check. The checking is the loop, and the time is the guess about when the loop will have finished.
The oven is the same kind of thing, and it is a balancing loop with a much bigger delay. An oven heats up, holds, and cools down, and you open the door and the temperature falls and it comes back. Opening the door while the cake is in is a bigger intervention than it looks, because you are knocking the system off its target and the cake experiences the recovery. This is why the advice about opening the oven door is really advice about not disturbing a balancing loop that has a long delay.
Which things can wait
The single most useful question in cooking for a crowd is not what to make. It is: while this is cooking, what else can I be doing?
Some tasks cannot overlap with anything. Making a roux needs a hand and a burner and attention. Chopping needs a hand and a board and no burner, and it can happen while anything at all is cooking. Resting meat needs nothing whatsoever for half an hour. Setting a table needs nothing. Washing salad needs a sink and no burner. These are the tasks that go in the gaps, and a plan that treats the burner as the only resource will fill the burners and leave the cook idle, and then run out of time at the end.
There is a second question hiding behind the first, and it is the one that turns cooking into a design problem: what does each finished thing need next, and how long can it wait? A roast needs to rest. Vegetables need to be hot. A salad needs to be cold. Chips need to be eaten immediately or they are disappointing. A cake is fine for an hour. A soup is better for a while and then not. So the order is not only about the stove. It is about the queue in front of each dish, which is the time between it leaving the heat and it being eaten.
What if you had two people cooking instead of one? Everything changes, and not just because there are twice as many hands. Two people can be at two burners, but they can also be at the same dish, which is often a waste, and they can split the work into two streams, one of which handles the things that need hands and the other of which handles the things that need waiting. The plan is different, and so is the bottleneck, and so is the order. With two cooks the constraint is often the oven and the shared ingredients, not the people.
Now change the condition. What if you had one cook but two stoves, one of which was a hotplate you could put on a table? The capacity is the same and the plan is not, because now the attention is still the constraint and the burners are not. The hotplate lets you run a slow thing unattended while you work on something that needs hands, which is the only kind of parallelism that matters when there is one pair of hands.
"Cook the things that take longest first." It is a decent rule and it is not the rule. The oven wants its fixed-time things early, because they can wait afterwards. The stove wants its longest thing early, because it needs the burner. But a thing that can be left alone for forty minutes and a thing that must be watched for forty minutes are not the same, and the second one is the one you should not start at the beginning of the evening, because you will be standing next to it for the whole of the busiest part of the cooking.
The other misconception: "the recipe is the plan." A recipe is a set of instructions for one dish, made by somebody who was cooking one dish. A plan for six is a schedule, and the two are different objects, and the difference is that the schedule is about what can happen at the same time. Six recipes multiplied together is not a plan. It is six plans played one after another, which takes three times as long as it needs to.
Why dinner is rarely about the stove
It is tempting to think of the cooking as the work and the serving as the easy part. It is usually the other way round, and the reason is that the cooking is bounded and the serving is not.
The cooking has an end. It is done when the last thing is out of the oven. The serving has no end, because serving is a series of small decisions about people, and it goes on as long as there are people at the table. Somebody does not eat. Somebody is late. Somebody has a birthday. Somebody has a condition that makes a particular dish a problem. These are not the same kind of problem as knowing how long to cook something, and the recipe is no help with any of them.
And this is where the system view earns its keep, because the cooking is a loop with a delay and the serving is a structure with a constraint, and they are the same system. The constraint in the serving is not the stove. It is the person who is doing the serving, and the person who is doing the serving is usually the person who was cooking, and they are now needed in two places at once. A plan that ends when the food leaves the oven has not planned the meal. It has planned the cooking.
Limits
This essay uses a domestic kitchen and a small number of people, and the shape does not scale up cleanly. A kitchen with six burners and three cooks and a combi oven is a different system, and the constraint moves to the passes, to the mise en place, and to the communication between the cooks, and a lot of the reasoning here becomes irrelevant. The general form survives, which is that there is one scarce thing and the order is decided by what can happen without it, but the specific answers change completely.
Second limit: heat is a loop but a good cook is not running a loop, and this is worth admitting because the loop picture can be overdone. A loop that is only corrected by continuous attention is a bad loop. A dish that has to be watched for its whole cooking has been designed badly, and the design that fixes it is to give it less to do, so that the loop can run itself for longer.
Stuck
You are stuck at the system level with a meal when you are following the recipes one after another and running out of time. The tell is that you are doing the cooking and none of the other work is getting done, and by the time you look up, the potatoes have been waiting for eight minutes and the salad has not been started.
The way out is to stop looking at the recipes and start looking at the gaps. Write down what each dish needs, and when it needs it, and then look at the ten-minute gaps that will inevitably appear in the middle of the cooking. Put the chopping in the gaps. Put the resting in the gaps. A gap is not wasted time, it is the only place where the work that does not need the stove can happen, and a plan that does not fill the gaps has simply decided to do the jobs one at a time.
Sources
- The constraint, attention, and critical path ideas are used here in their ordinary sense, applied to a domestic kitchen. No specific method or author is cited, because the example does not need one.
- All recipes, times, and dishes mentioned are illustrative. No specific cooking times are given as advice, and none of the timings should be relied on.