Creating specialty milk-based coffees
I love drinking black coffee. I drink it all day and in all its forms, whether it's a beautiful filter coffee or a sensational espresso. Working in a coffee shop, however, most of my customers are more interested in milk beverages than anything else, including both plant based and dairy milks.
A lot of baristas might turn their nose up at preparing and serving milk-based coffees, thinking that they are inferior or ‘less specialty’ than black coffee. However, there are ways to serve our customers the best possible specialty coffee experience with milk-based beverages, without compromising the idea of specialty and delivering an unforgettable coffee.
In this blog post, I want to write about my experiences working as a barista in both Germany and Australia, and explore how to create the best milk-based coffee possible – to do that, I’ll look at coffee selection, extraction, ratio and temperature.
Let's start with the choice of coffee.
As specialty coffee has become more mainstream over the last decade, the general consumer has come to understand the difference between different roasts, ie espresso and filter. However, as many roasters are now also blending and roasting specifically for preparation as milk-based coffees, this has added a third category to communicate.
In the shop I work at in Berlin, we have always had 2 standard blends on the grinders. One is (a) our milk based blend, a combination of full bodied coffees with a high percentage of natural processed beans, that tastes chocolatey and a bit heavy. The other blend (b) is a combination of two washed Africans and one washed South American coffee. In this particular combination you can really taste the florality and lightness of the Ethiopian coffee, paired with the juicy, red berry qualities of a Kenyan and to elevate the body of this coffee and give it a round finish, the South American bean combines all those flavours and gives it a chocolaty finish.
Both coffees taste great by themselves – but while blend (b) develops a very fresh and fruity taste experience and tastes best on it’s own, the more chocolate-driven blend (a) has an amazing potential to be used in a milk beverage. The natural sugars in the milk add extra sweetness to the beverage, pairing with these chocolate notes in blend (a) to create a delicious coffee. If we were to add milk to the more floral and fruity blend (b), these more delicate flavours might be overpowered or washed out by the milk and this pairing might not go so well.
So, we have these special coffees blends designed to be drunk either black (as espresso or americanos) or as milk-based coffees, in order to give the customer the best experience possible. As we’ve read, we know that picking up any coffee roasted for preparation as espresso and adding milk doesn’t always turn out the way we plan, due to the flavour profiles and body of the coffees.
When we are mixing coffee with milk or plant based milk alternatives like oat milk, we need to consider the gigantic dilution that is going to happen to our (usually) single shot of espresso. That's why we should use strong-bodied coffees that have a chance to keep up with dilution. In my experience, natural processed coffees work fantastic for this use, and in roasting we look to increase the development time (the time between the ‘first crack’ and the end of the roast) in order to increase body and caramelisation in these coffees.
What I also came across during my time in Australia is the use of carbonic maceration coffees or anaerobic processed beans for milk-based coffees. Their character is also quite heavy and sometimes even a little bit boozy. In combination with milk, I could really elevate my drinks and suddenly I had the most insane sweet fruit qualities in my milk drinks, such as banana, blueberry muffin or raspberry candy.
Learning about those coffees has changed the way I look at milk beverages now. I’ll admit that I always saw them as a compromise to great quality and as boring, but with those coffees I got hooked. I was, and am excited about how I can dial in these coffees, and which milk ratios I can use to create something truly special.
Extracting espresso for milk drinks
Due to the dilution I mentioned earlier, I have learned that the espresso that you use for this course should be dialled in quite concentrated. If you dial in an espresso by itself, let's say you would use a 1 to 2 ratio like 18g in and 36g out. This extraction gives you a balanced espresso. If you extract 38g out you might even get a more juicy finish and a lighter drinking experience. If you combine this coffee now with, let's say, 120g steamed milk, all those amazing qualities might get lost or overshadowed.
What I have learned instead is, to create a more concentrated version of this coffee by decreasing the brew ratio (such as 20g in and 35g out). This way it will not be the best version of itself without milk, but with milk it can keep up with the milk and still be present, even if we diluted it.
As a coffee cocktail competitor I like to compare this to a harsh spirit like Vodka. By itself, it might be way too harsh and a bit too intense to drink – however, if the Vodka is the right quality and if we dilute it with soda water and maybe a slice of lime, we get one of the most refreshing drinks ever. It shows how much we can benefit from using the right ratio.
How important is milk to coffee ratio?
Another important variable to consider is the size, or volume of the cup that you will be using for your milk beverage. The ratio I use in our shop at the moment is a single espresso with 19g on 110g steamed milk – with this recipe, the milk makes up about 85% of the beverage.
Now if you have ever weighed your milk during your dial in (which I recommend), you’ll realise that what I am using day to day is a pretty small cup. It’s not tiny, but it is also not gigantic.
When I look at different cups in the market and available at other shops, I realise that they have a standard size of about 200mL (which would mean that milk makes up about 90% of the beverage). How should any espresso be able to hold up against such a huge amount of milk? Assuming they’re using a similar amount of espresso in each cup, this amount of milk would literally drown or wash out the coffee flavour entirely.
This is why we should really focus not just on the look of our cups, but also the functionality, total brew weight and the coffee to milk ratio. By dialling in every single espresso in the bar at the start of the shift and tasting the different expressions those coffees have, I learned to adjust milk amounts and extraction yields every day. Over time, I have found that even 10g more or less of milk will drastically change the flavour of a milk-based coffee beverage.
To control the milk amount we are using at the bar, we use automated milk foaming systems such as Uber Milk. I have worked with this device and find it incredible how much you can speed up your workflow and simply get so much better at making amazing milk coffees with incredible consistency. Those machines help the barista to use the same amount of milk per cup, as well as the same temperature and the same consistency every time. If you’re making milk-based coffees at home, you obviously won’t have a machine like this – however, the more consistent you can be with your texture and temperature, the better.
Temperature for milk-based coffees
Milk sugars / lactose absolutely elevates the flavour and sweetness of our coffee. But at the same time, these components of milk are very sensitive to heat. If we apply too much heat, the lactose and sugars will caramelise too much and turn bitter, just like if you caramelise sugar too much.
Likewise, the behaviour of the protein structure in different milks will drastically influence the flavour profile and overall experience of milk-based coffee; if you heat up UHT milk, a 4% fat dairy milk and oat milk all to the same temperature, they’re all going to have different textures, mouthfeels and all create different flavour experiences.
When using fresh dairy milk, currently the most popular milk for specialty coffee, my preferred milk temperature is around 63 degrees. When using plant based milks such as oat milk (see my blog post about plant based milks here), I prefer to keep the temperature a bit lower – this stops the protein structure of the oat milk creating a dry mouthfeel, which occurs with excessive heat.
From the preparation of espresso and filter coffee, we know how flavour profiles and tactile in coffee can change depending on the temperature. The same occurs in milk drinks, and the experience of a boiling hot milk coffee is very different from that of a milk coffee at a good temperature. When preparing your milk coffees, I would strongly recommend checking your milk temperature with a thermometer, to see whether you are steaming too hot or too cold. Like with a lot of coffee topics, it is all about finding the sweet spot.
In my time working in the coffee industry, I have felt like I have done a full 360 turn. I first began working behind a machine preparing milk-based coffees, then gradually ‘moved on’ to competition-style espresso and filter coffees, exclusive micro-lots and experimental fermentation. However, I have realised that it’s not much use focusing on the smallest percentage of coffees served, like these rare and experimental lots, if the main beverages we are serving are not the best they can be.
By focusing on the different variables in the preparation and serving of milk-based coffees, I believe that we can further elevate consumer experience and education on a faster and bigger scale. By educating other baristas and customers about milk temperature, special roasts for milk-based coffees and specific coffee-to-milk ratios, we can help to increase awareness and knowledge of the specialty coffee industry.