When the egg floats: a practical guide to knowing what to keep and what to discard

Standing in front of the refrigerator with the door open, we inevitably wonder: is this food safe to eat? The reality is that knowing how to identify whether something should be discarded or if it’s still safe to consume is an art that combines science and observation. Especially when an egg floats in water, a clear sign that something has changed in its condition. We consulted food experts to uncover the secrets of preserving three essential kitchen staples: cheeses, eggs, and chocolate.

The art of storing cheeses: how to distinguish safe from dangerous

We often find cheeses with an appearance that makes us uncertain. Elena “Betty” Coste, sensory analysis specialist and PhD in Food Technology, helps us interpret what we see correctly. A “bad” appearance doesn’t always mean the product is spoiled; sometimes it’s just natural aging.

Immediate rejection signs include an uneven surface, irregular rind, visible cracks, or deep holes. If the smell is unpleasant and excessively moldy, that does indicate a serious problem. However, white or green molds that appear on the surface inside the fridge are generally not toxic and can be easily removed.

The key to properly storing cheeses lies in the wrapping and placement. Ideally, keep them in the bottom drawer of the fridge, properly protected. Hard and semi-hard cheeses should be wrapped in plastic wrap to prevent drying out, while mold-ripened cheeses (like blue cheese or Camembert) require aluminum foil. Fresh cheeses with high moisture content, such as mozzarella and cream cheese, should stay in their original container at 4°C, preferably in the upper part of the fridge.

The water test: how floating eggs reveal freshness

Tomás Gil, food engineer, teaches us the simplest and most effective trick to assess whether a raw egg is fresh: the float test. This ancient method works because eggs age and lose density over time.

The procedure is straightforward: fill a glass with water and place the egg inside. If the egg sinks to the bottom, it’s fresh and suitable for any preparation. But when the egg floats, it indicates that it has aged and should be evaluated carefully before consumption. Besides this test, other indicators include a very watery egg white, black spots when cracking the shell, or a strong, rotten odor—signs that it should be discarded.

Hard-boiled eggs: proper storage for up to a week

When preparing hard-boiled eggs to have them ready, proper storage is essential. The first step is to cool them quickly after boiling; this prevents the greenish halo around the yolk, which indicates overcooking. The shell acts as a physical barrier against contaminants, so it’s best not to peel the eggs until ready to eat.

In the fridge, stored in an airtight container, cooked eggs can last between five and seven days. This knowledge helps make better use of preparations and reduces waste. However, the most recommended practice remains cooking only what will be consumed.

Properly stored chocolate: avoiding waste of this treasure

Contrary to what many believe, storing chocolate in the fridge is not the best option. Diego Armanini, master chocolatier, explains that chocolate thrives in cool (16 to 20°C), dry places, away from direct light and high humidity, always in airtight containers. Cocoa powder requires an airtight jar or can, kept away from heat and strong odors.

Distinguishing good quality chocolate from spoiled is crucial. If you detect mold, rancid smell, sour taste, or a moist texture, discard it. In the case of cocoa powder, the presence of insects also indicates immediate rejection.

However, some aesthetic defects do not mean spoilage. White spots known as “fat bloom” or “sugar bloom” occur when fat or sugar migrates to the surface due to sudden temperature changes. The chocolate remains safe to eat or melt. If cocoa powder has dry lumps but smells correct, it can also be used without issue.

The approximate shelf life is: dark chocolate between 12 and 15 months, milk or white chocolate between 9 and 12 months, and cocoa powder around 18 months. Understanding these distinctions allows us to optimize our purchases and avoid discarding foods that are still safe, while protecting your health by discarding only those that are truly compromised.