If your milk’s not frothing right, it could be the season, how fresh it is, or your technique. Hot or dry weather may alter the milk’s fat content and affect the foam.

If your milk isn’t frothing properly, there may be several factors as to why. Whole milk is pretty consistent year-round, but there are a few behind-the-scenes things that can affect how well it froths, especially at certain times of the year. 

In late autumn and winter, cows are usually in the later stages of their milking cycle, and the fat in their milk breaks down more easily (a process called lipolysis). That breakdown creates stuff that actually makes it harder for milk to foam up properly. Also, during hot months or droughts, when fresh grass is scarce, cows get fed more grains or silage, which can have a similar effect on the milk fat.

Beyond that, here are a few other things that can affect how your milk froths.

• Protein content: Higher protein content usually leads to better frothing. It’s worth noting that whole milk has a set minimum protein level, usually around 3.3%, so protein levels stay fairly stable throughout the year.
• Fat content: Whole milks usually produce a creamier, denser foam, while skim or lite milks usually produce more volume and a lighter foam.
• Temperature: Aim for 55–65°C when frothing milk. Too cold = no foam. Too hot = proteins break down and the foam flops.
• Freshness counts: Milk that’s been open for a while might not froth as well.
• Your technique: Getting the right mix of air and heat with a steam wand is key.
• Your equipment: A proper steam wand gives the best results. Handheld or automatic frothers can work, but they vary.

So, if your milk’s suddenly not playing nice, it might be a mix of seasonal changes, how fresh it is, or how it’s being frothed.