Fable
Fast kitchen and flowing banquet
Old Ma's restaurant had two kitchens. On the left was the "fast kitchen," which made only one dish. When a guest ordered, the chef heated the pan, stir-fried, plated, and served—from order to table in as fast as three minutes. On the right was the "banquet line," which made an entire table at once, eight dishes served simultaneously. But you had to wait—prepping ingredients, cutting, plating, and coordinating the heat meant the first dish would not reach the table for at least twenty minutes.
When the restaurant first opened, it focused on fast cooking. Customers ordered and ate within three minutes, word of mouth was good, and table turnover was high. Later it took several corporate group meal orders, requiring dozens of portions at once, and fast cooking could not keep up—although each portion took only three minutes, there was only one stove, so later orders had to queue, and by the fortieth portion customers had already waited more than an hour.
So Old Ma expanded the buffet kitchen. Eight stoves worked at the same time, producing more than a dozen portions at once. The company group meal problem was solved, but a new problem appeared: à la carte orders from individual diners were also routed into the buffet kitchen. A customer ordered egg fried rice and waited twenty-five minutes without it being served. The server ran to the kitchen to urge them on, and the chef said they were cooking large pots of food, and single portions would have to wait until this pot was finished before being inserted.
Old Ma sat down to review. Quick Kitchen's per-portion time is three minutes—that's called low latency, but the number of portions it can produce per unit time is small—that's called low throughput. The banquet line's first dish takes twenty minutes—high latency, but it can put out over a hundred portions an hour—high throughput. Each kitchen has its strengths; the problem was sending a walk-in customer's egg fried rice into the banquet line's queue.
Old Ma set up a split in the checkout system: walk-in orders automatically went into the fast-kitchen queue, while group meals and bulk orders went into the banquet queue. The two kitchens operated independently and were no longer mixed. Walk-in customers still got their food in three minutes, and group-meal clients received their full tables on time.
Later a peer asked Old Ma: Didn't you say the buffet has high throughput? Why is a single serving actually slower? Old Ma said: High throughput comes from starting in batches. A single serving going through the batch channel has its advantage eaten up by startup cost. If you have a sports car haul a load of bricks, it's not even as fast as a tractor.
Old Ma posted a rule on the kitchen wall: for speed, ask the quick-order cook. For total volume, ask the banquet line. Do not use the banquet line's numbers to explain the wait time for a single dish.
On the first day of work for the new chef apprentice, Old Ma first took him to two walls. On the left wall were the rules of the fast kitchen: one portion in three minutes, the stove never waits idle. On the right wall were the rules of the banquet line: one pot makes more than a dozen portions, coordination never yields the stove. Old Ma said: choosing the right kitchen matters more than burying your head in cooking.