Yesterday I opened a can of navy beans and was greeted by a strong, cheesy smell. This followed the spray of carbonation that zinged out when I began opening the can—a sure warning sign. But the smell! It was unmistakeably wrong.
When I looked at the beans, their liquid was creamy white, not clear. I opened another can of navy beans, and they 1) smelled mildly of beans and 2) were floating in clear liquid. Out to the compost went the smelly beans. We’ve come to trust the overall quality of commercially-canned foods, so opening a can of fermented beans is quite uncommon. But those bad beans were a good lesson in the importance of smell.
We eat using all five senses, so it makes sense that we would use them all when we cook, too. This is especially significant when something can be spoiled without changing its appearance. Just last week, both tofu (looking otherwise fine, but smelling strongly of baked cheese) and an egg (appearing fine but smelling irrefutably OFF) might have tricked me if I hadn’t detected their unexpectedly strange odors. Again, the smell of these spoiled foods saved the day.
One of my clients, with the help of her curious, culinary-minded daughter, has undertaken the Tartine bread project featured in last Sunday’s New York Times. This is a fastidious recipe which builds a starter over the course of a week by discarding and feeding a small amount of flour/water each day to another small amount of flour/water. The ambient yeast—those yeasts occurring naturally in the environment and for which San Francisco is especially renowned—will make a home in this mixture, and fermentation will take root. By day seven, this pungent, lively, yeasty concoction will become the foundation for what looks to be a splendid loaf of bread.
Reading the starter’s progress each day is a great lesson in the necessity of sensory observations. As the top of the starter can take on all manner of appearances (though actual mold is a sure sign you need to start over), the nose becomes your best gauge of the starter’s health. Taking a good smell of it each day will tell you if it’s still on track; it should smell faintly and cleanly sour, but not cheesy (think baked cheddar) or moldy (as in moldy bread). As the starter, and its resulting bread, continue to develop (and this particular recipe is a two-week process), paying attention to the smell of the dough will remain a good practice. Such organic processes, happening in a relatively uncontrolled environment, require a special vigilance but also provide wonderful rewards; chemistry in action happens before your very nose.
When clients ask me if they can still consume leftovers after X number of days, I always advise them to smell the food. The nose does not lie. If you are too faint of heart to undertake such a task, have a friend do it for you. (The dog, though renowned for its sense of smell, is an unreliable source in such matters, since anything given is worth eating, and the more disgusting, the better.)