I am admittedly not a huge coffee guy. I actually much prefer a nice cup of hot chocolate any day of the week. With that being said, it is undeniable that Fall has one drink to rule them all: the Pumpkin Spice Latte. A subset of the caffè latte family of drinks with some special spice, it’s a favorite amongst many at this time of year. Now, you may ask yourself, what makes a latte a latte? Disclaimer: Coffee snobs, piss off, and don’t even think about correcting me on any of this — it’s called an Opinion Column for a reason. Moving on, it’s essentially espresso with foam on top. But not just any foam microfoam. Also known as wet foam, as opposed to macro or dry foam, microfoam has microscopic, evenly dispersed bubbles. This makes it ideal for creating latte art and staying afloat atop the latte.
It was while I was researching for this article and I read the term “microfoam” for the first time that I said to myself, “Holy fuck, is the most research I am going to have done for an article really going to be about coffee?” Yes, yes, it was. I got to polish up on both my chemistry and electricity and magnetism knowledge. For instance, microfoam is a colloid, a colloid being a substance with a medium and dispersed particles throughout. The milk is the medium, and the air particles are the gas. But it does not stop there because milk itself is a colloid, an emulsion. That’s because milk is just a mixture of typically immiscible fluids: oil and water. Now that we have the chemistry down, how does one make microfoam? Well, if you are professional and own a latte machine and the like, you use a jet of hot steam to simultaneously heat up the milk and aerate it. I, however, am neither of those things. So, I will discuss the humble handheld milk frother.
The only prerequisite to using the milk frother is heating up the milk ahead of time. Once you have the milk at a cool 70 degrees Celsius, you are ready to begin. Tilt the cup to a 30-degree angle, insert the frother, and turn it on. Initially, you will be able to see the frother head as it incorporates air into the milk. Once the milk has covered the frother head, continue frothing until all visible bubbles have disappeared. We have now reached the actual point of the column. Quite frankly, I am stunned and humbled to think that you have read this far. So, just how does a handheld milk frother work?
Handheld milk frothers are glorified miniature mixers. They have a long shaft with a whisk, which I like to call a frother, at one end, and the other end is affixed to a DC motor. Upon dusting off my four-year-old notes at 8:27 a.m. on a Thursday, I can say that direct current motors work via direct current! Simply put, when you pass electricity through a wire, it generates a magnetic field. If you bend that wire into a loop, it’ll create two poles, north and south, above and below the loop. Surround that loop with two permanent magnets, one that’s north and the other that is south, and those magnets will spin! But you may be saying to yourself, won’t it spin for a little bit and then get stuck once north meets south and south meets north? Indeed, you are right, but if we reverse the flow of electricity in our wire loop, our north and south poles will also flip! Time those current switches correctly, and you will get a constant spin. Add more and more of those loops and more and more magnets, and then you get yourself a DC motor. I have definitely gone over my word count on this one, so I’ll see you guys next time when we will be getting Sp00ky. 😉
