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

To make pickles, you need to create the right conditions to encourage “good” bacterial growth, 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 tart flavor and discourages the growth of bacteria that will spoil pickles.

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

It is vital to keep oxygen away from fermenting vegetables. Oxygen encourages 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 spoilage bacteria an advantage and ruin your pickles.

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