Highway From the (Food) Danger Zone

Saucyman, I went to make soup this weekend. Every cookbook, each recipe instructed me to heat the contents up to a boil and then reduce the temperature. What is the logic in this? – Simmering

There are two reasons for instructing cooks to hurry up and wait. The first is to move food quickly out of the food danger zone. Heating liquids to a boil is like pasteurizing cream - by heating contents the threat from the icky stuff has been neutralized.

Bacteria love temperatures between 40º - 140º ƒ (5-60 C) – organisms will multiply in this temperature range. By bringing the contents in your pot to a boil - 212º ƒ (100 C), you are most assuredly killing off things like the 2,300 different strains of Salmonella, who abhor temperatures above 165ºƒ (75 C). E. Coli is mostly taken care of when temperatures reach 155ºƒ (68 C); the possibility of Trichina Spiralis a.k.a trichinosis is negated at 150ºƒ (65 C); Listeria doesn’t like it above 160ºƒ (70 C).

The second purpose for having cooks boil first then reduce the temperature has to do with the vagueness of the term simmer. For what it lacks in nuance, English is usually more precise than Romance languages. An exception to this rule is in the kitchen: For those who cook in French – language not cuisine – there are 2 separate words for cooking liquids below the boiling point. Mijoter is the equivalent of simmer - the point that small bubbles rise to the surface of a pan. If a simmer/mijoter was too rough and tumble for a dish, those working a la Francaise would be instructed to fremir, which is something between a poach and a simmer, where the cooking liquid is kept low enough so no bubbles form.

Back in English, writing a recipe that instructs soup makers to “Simmer” causes a couple problems. There is there isn’t a common definition for a simmer. Although most people accept 180ºƒ (82 C) as a simmer, some consider 160º ƒ to be simmering – things like a 10% difference in temperature matter in cooking.

Along the same lines, if a recipe states to simmer for 90 minutes, how quickly you reach a simmer makes a difference. Not all kitchens are created equal - A spiffy copper/clad/anodized pan heated up on medium over a gas burner is going to get hotter quicker than a cast iron pot placed heating up on a medium setting over a small electric burner. The fancy pants equipment might get the contents of a pan to 180 degrees in tens of minutes, while the combination of a heavy pan cooking on a small heating element could take hours to reach a simmer. Telling cooks to first bring a pot to a boil, then reducing heat and cook for ‘X’ amount of time erases any discrepancy in equipment – everyone is working on a level playing field.

Being safe and consistent might not be the most exciting way to live life, but it isn't a bad thing when making a pot of soup.