You can turn almost any cooking recipe into a science lesson, maybe even a science project for school. Let’s look at fermentation in pickling. Salinity, pH, oxygen and temperature are variable factors that determine the outcome of your pickles.

To make pickles, you must create the right conditions to stimulate the growth of “good” bacteria, while slowing down the growth of “bad” bacteria. The good bacteria digest the sugars in vegetables to create lactic acid. Lactic acid gives pickles a distinctive sour taste and discourages the growth of bacteria that will spoil the pickles.

Salinity (salt concentration) is an important factor in the pickling process. If too little salt is used in the brine solution, bad microorganisms will grow fast enough to cause spoilage. With the right concentration of salt, lactic acid bacteria have an advantage over bad bacteria. Lactic acid is produced, which creates flavor and lowers the pH of the solution. This more acidic environment keeps harmful organisms at bay. Too much salt prevents lactic acid-producing bacteria from growing and cucumbers will not pickle. Some yeasts can also grow faster, consume lactic acid to raise the pH and allow spoilage.

It is vital to keep oxygen away from fermenting vegetables. Oxygen stimulates the growth of bad bacteria and promotes spoilage. Also keep pickles and brine covered during fermentation.

Lactic acid-producing bacteria are happiest at 70 to 75 degrees F. Higher or lower temperatures can give bacteria an advantage to spoil and ruin your pickles.

An interesting science project could vary the above factors to see how the pickling process is affected. Of course, do not eat any results that can be spoiled.