Dear chocolate lovers and praline devotees,
As the famous movie quote goes, “Life’s like a box of chocolates. You never know what you’re gonna get.” A delicious treat, available in countless varieties, it deserves looking after. Just how do you safely store chocolate?
It’s a warm summer’s day. You’ve left chocolate out on a windowsill or in the car. When you finally notice it, it’s inevitably turned into something resembling sticky chocolate milk. In a desperate attempt to save it, you hurriedly slam it in the fridge . Later, you’ll discover that your re-hardened chocolate doesn’t look appetizing any more. Apart from an expected change of shape, white marks have formed on its surface. It’s easy to assume that refrigeration actually harms it in some way. Surely chilling it must have a detrimental effect on its taste? Shorten its shelf life? Is it really okay to keep it in a refrigerator, let alone a freezer?
Let’s find out!
Chocolate Science: Influencing Storage Factors
When chocolate comes into contact with air and light then a process known as oxidation occurs, and this means that the fat contained in the chocolate changes into other substances leading to marked impairment of the flavour and to an unappealing smell. The cocoa in chocolate contains natural substances that slow down this oxidation process. Dark chocolate, with a relatively high cocoa content, is better protected against the effects of oxidation than milk chocolate. White chocolate, on the other hand, doesn’t contain cocoa constituents. It doesn’t have this protection at all and is therefore particularly sensitive to exposure to air and light. In order to prevent oxidation, you need to store your chocolate in airtight, lightproof packaging.
Substances from the surrounding environment can diffuse through the packaging into the chocolate. Water or alcohol can diffuse out of any chocolate filling into the environment. That’s why chocolate is nowadays often packaged in sealed plastic. Many of us are also familiar with chocolate that is wrapped in aluminium foil with an outer paper/cardboard wrap.
Similar to what happens with ice crystals, small cocoa butter crystals become larger over time, due to an effect known as Ostwald Ripening. These crystals can develop at the surface, becoming visible as a white deposit – a “fat bloom”. The process is promoted by temperature fluctuations. You might have noticed this phenomenon if you have left chocolate out on a cold windowsill overnight. As it warms up again through the day, the chocolate begins to “sweat”. Cocoa butter is deposited on the surface, creating an unappetizing white coating. This coating isn’t mold and is neither harmful to the taste nor your health.
Chocolate has a water content of about 0.6. Without protective packaging it can quickly absorb moisture, resulting in the “fat bloom” mentioned above. In the worst case scenario, even mold. Packaged chocolate is extremely safe from a microbial perspective. Due to its very low water content, spores are barely able to multiply on it.
Odour and taste transmission:
Fat-soluble chemicals, found in cheese, fish and meat aromas, are quickly absorbed by chocolate. It can easily smell and taste “old”. White chocolate in particular quickly absorbs ambient smells. It should be kept in airtight, fragrance-neutral packaging.
Cocoa butter comes in different crystal forms. The type III and type IV crystal forms are eliminated during manufacturing. Only the desirable type V crystal form remains in the chocolate we buy. Type V crystals have a melting point of around 32°C, which means that chocolate, quite literally, melts in the mouth! At higher temperatures, like when chocolate is left inside a car in summer, larger type IV crystals form, which have a melting point of 37 °C. As a consequence the chocolate no longer tastes so good and it no longer melts in the mouth.
Storage in Your Freezer:
Freezer storage tests at -18 °C showed that the chocolate’s sensory properties were preserved very well. If you wish to preserve treats that you can only get during the Holiday season, for example, a freezer is your best choice.
Storage in Your Refrigerator:
If chocolate remains in its packaging, it can be kept in a refrigerator at any temperature and humidity for months, without any impairment to its flavor and odor. Should the packaging be open, it needs to be stored in an airtight container. That way it doesn’t absorb foreign odors.
Comparative tests between storage at room temperature and storage at refrigerator temperature have shown quality differences became evident at the earliest after around 3 months or 6 month in the case of sensitive chocolate truffles or “normal” full milk chocolate respectively. In the case of “critical content”, like pralines with a cream filling, storage in a refrigerator is most definitely recommended from a microbial point of view.
• Chocolate can be kept “fresh” in a freezer for several years.
• Storing chocolate in a refrigerator is better than at room temperature (about 20°C).
• There are no particular temperature or humidity requirements for storing packaged chocolate in a refrigerator .
In the author’s opinion, it is best not to store this most wondrous temptation, seduction and pleasure for too long. Eat it, without delay! Most chocolate delicacies should simply be sampled as soon as feasibly possible! Many fellow aficionados will find themselves agreeing wholeheartedly with Irish author Oscar Wilde: “I can resist anything except temptation.”
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