The Top Milk Steaming Mistakes by Home Baristas

Steaming a pitcher of milk with the rhinoware pitcher on the La Marzocco Linea Mini Espresso Machine

One of the trickiest things to learn without hands-on training is milk steaming and latte art. Without an instructor guiding you, it can be hard to know what’s going wrong, especially when all the advice on the internet tells you what you should be doing, and if it were really that easy, we wouldn’t have felt the need to create this blog. We’ve seen thousands of students online and in our classroom in Portland experience immediate success and improvement in their foam quality, after taking our milk steaming class. So, we decided to compile some tips and advice to unpack the top mistakes baristas make when it comes to steaming milk that’s latte art ready. 

1. Using too much or not enough milk

To create foam for a latte, you must push air into the milk with the steam wand — this is called aeration or stretching the milk. The goal is to expand the milk’s volume by about ⅓. If you use too much milk for your pitcher size, you won’t have enough room to properly stretch the milk without the risk of overflowing your pitcher. If you don’t use enough milk for your pitcher size, you won’t leave room for the steam wand to submerge underneath the milk's surface, which could create too much foam or blow out the milk, especially if you have a powerful steam wand. Use a pitcher that’s a few ounces larger than the drink you’re making and fill it just below spout or about 3-4 fingers length from the bottom. The goal is to have enough room to expand the total volume of milk by about ⅓ and be left with enough room to swirl the pitcher around to prep your milk before pouring a latte. When you pour, you should be left with only a thin layer of milk at the bottom of the pitcher. Play around with your cup and pitcher size and how high to fill the pitcher with milk. 

2. Improper steam wand placement

Wand placement is critical. The wand should be halfway between the center and wall of the pitcher to encourage a vortex that incorporates foam as you create it. More often than not, baristas either have it too far to the side, making a milk whirlpool that can quickly get out of control. If the wand sits dead center, the milk will look more like a jacuzzi when steaming — bubbling up and splashing everywhere. The correct angle will make a better final product. The other position you need to be cautious of is depth placement. We recommend starting with the wand just slightly under the surface of the milk so that when you turn on your steam wand, you don’t blast milk everywhere. If the wand is above the surface when you turn it on, you’ll experience what is referred to in technical terms as a milk explosion. If the steam wand is under the surface of the milk, you’re safe. So don’t be afraid! Once the wand is on, slowly lower the pitcher until the wand is just kissing the surface — your queue for this is a gentle, paper-tearing sound. You’ll know you’re in the right position when that happens. 

3. Aerating at the wrong times

One of the biggest mistakes baristas make is aerating at the wrong times. The difference in foam created while the milk is still cool compared to when it’s warm is dramatic. To get latte-grade microfoam, you must aerate or stretch the milk while it’s still cold — before the milk passes 100 degrees Fahrenheit. You can either use your hand or a thermometer. Depending on your steam pressure, you may need to aerate all the way until you reach 100 degrees or only for a second or two. This takes some experimenting. If you wait to aerate until the very end, you’ll be left with large seafoam-like bubbles that stay separated from the milk. If you aerate the entire time, you’ll have an abundance of extremely stiff foam. If you don’t aerate at all — you’ll finish with just very hot milk. If you don’t aerate enough, the milk will let you know (hold your hands over your ears, it’s a loud one). Once you reach 100 degrees or have created the amount of foam you like, submerge the wand back underneath the surface until you have finished heating the milk to its final temperature.

4. Improper temperatures

Milk not only aerates differently at various temperatures, it tastes differently, too. When you introduce heat to milk, the sugars break down, making the milk much sweeter. However, if you overdo it, it can curdle, taste sour, and ruin the foam. Ideally, the final temperature should sit between 130-150 degrees with a general rule of alternative milk at slightly cooler temperatures. To ensure you reach a high enough final temperature, it’s important to hold the pitcher properly. Most people aren’t able to keep their hand on a 140-degree metal pitcher for more than a second or two — so we recommend holding the pitcher by the handle and using your other hand to work your machine and gauge for temperature. You should be able to hold your hand on the side of the pitcher for a couple of seconds. This isn’t the most accurate since everyone has a different tolerance for heat so do. Do a taste test to figure out how hot you like your lattes and how long it takes for your machine to reach that temperature.

5. Steaming all milk types in the same way

Every type of milk has a different makeup of fats, sugars, and proteins. They will not all steam the same. The higher the fat content, the more you’ll need to aerate. You’ll need to aerate low fat milk less than whole milk and half-and-half for breve lattes for longer amounts of time. If you prefer non-dairy milk, make sure to seek barista blends as these have been formulated to steam as similarly to whole milk as possible. 

6. Not grooming milk after steaming 

Even if you steam your milk perfectly, take a moment to ensure your milk is ready for pouring latte art by grooming. Lightly tap any bubbles out of the pitcher and gently swirl it a few times until it’s nice and glossy. Liquid in the milk begins to drain from the foam after steaming — the longer it sits, the more it separates. If you steam milk before pulling a shot or let it sit too long, the milk may be hardly useable. If this happens, here's a quick tip — swirl the milk in the pitcher until the foam incorporates again, or try a pitcher transfer. It’ll never be as good as pouring immediately after steaming, but it can save the milk. Once it’s smooth and shiny, you’re ready to pour some latte art.

Get the hang of milk steaming first, then leave any thoughts, questions, or comments below, and we’ll be happy to help! Once you’re feeling good, you’ll be ready to pour latte art.