As an expert sommelier and brewer, I can confidently say that hot milk has a limited shelf life before it starts to spoil. Milk is a delicate liquid that requires proper storage conditions to stay fresh. When milk is heated, it undergoes changes that can accelerate the spoiling process.
Hot milk should never be stored in a flask overnight or for extended periods of time. The reason for this is that milk needs to be kept at a cold temperature to maintain its freshness. Hot milk stored in a flask will gradually cool down to room temperature, which is the ideal environment for bacteria to grow and spoil the milk.
Typically, milk can stay fresh for up to six hours inside a flask. However, this duration can vary depending on various factors such as the initial temperature of the milk, the ambient temperature, and the cleanliness of the flask. It is important to note that this six-hour guideline is not an absolute rule and should be used as a general reference.
When milk is heated, it undergoes a process called denaturation, where the proteins in the milk start to break down. This denaturation can affect the taste, texture, and overall quality of the milk. Additionally, the heat also kills off some of the beneficial bacteria naturally present in milk, which can further contribute to its spoilage.
In my personal experience, I have noticed that hot milk left out for too long tends to develop a sour smell and taste. It becomes thicker and curdles, indicating that it is no longer fit for consumption. These changes occur due to the growth of harmful bacteria, such as lactic acid bacteria, which thrive in warm environments.
To ensure the longevity of milk, it is best to consume it immediately after heating or store it in a refrigerator at temperatures below 40°F (4°C). Refrigeration slows down the growth of bacteria and helps to preserve the freshness of the milk for a longer period. However, it is still recommended to consume refrigerated milk within a few days to maintain its quality.
Hot milk should not be stored in a flask overnight as it requires a cold temperature to stay fresh. The heating process and subsequent cooling create an ideal environment for bacteria to grow and spoil the milk. It is important to consume hot milk promptly or refrigerate it to maintain its quality and prevent spoilage.