Milk Science

BH Unlimited Update, Oct 24th 2021.

Recently, an extremely popular Melbourne café let us take a look at their itemised till reading before they started cashing up for the day. You want to guess how many of the ~six hundred coffee beverages they sold on that day were milk based?

… A staggering ninety one percent to be exact! Customers love milky coffee — especially Aussies. A 91% majority signifies an interest level you’d think would make innovations in dairy farming and foam science the most talked about thing in the coffee industry. But we know that is not the case. When you look back on the training you’ve received as a barista, or you reflect on the interactions you’ve had with coffee professionals as a customer, how often was the discussion centred around milk science or dairy technology? From personal experience, I can say virtually never.

We think there are two reasons why milk is so much the elephant in the room. One reason is global warming. Dairy farming has a hopeless track record for emissions. The other reason is that foam science and dairy technology are extremely complex — there’s way more research and technology invested into it than there has been into coffee processing, and therefore, there is tonnes to learn. So it’s not an easy topic, nor an appetising one.

Can we agree that it’s impossible to convert 91% of our customers to black coffee? If you agree, then the most sensible action to take must surely be to confront this topic head on: Learn about the real ecological costs of dairy farming. Eighty percent of the waste in dairy farming is considered to be recoverable with existing technologies. However, there is a big deficit in the adoption of these sorts of technologies. For example, in 2014, of the 1,496 dairies in the state of California, only 26 farms had biogas technology installed. Of these, 17 had ceased using the equipment ( Libarle 2014 ).

If we, the customers, are properly informed, and interested in the subject, then we start to create the directive that we’d like to see the timely uptake of new technologies like biogas. And if the uptake of biogas isn’t happening because it’s fundamentally flawed, we want to know about an alternative. So in this week’s update, we’re bringing milk science centre stage, not only because we think it’s essential for baristas to understand all the ingredients they work with every day, but also because it’s fascinating. Over the last month we’ve been busy uncoupling the Milk Science part of MSLA course in order to give the topic the attention it deserves.

Any BH Unlimited subscribers can head in there and take a look at the new and improved Milk Science online course and certification . If you’ve already completed the MSLA course, you’ll notice a bunch of new videos, illustrations, quizzes and improved formatting across four chapters.

And here’s five fascinating foam facts from the course to help spark up some new conversations with your customers this Monday morning.

  1. A reason to texture your milk more carefully: Did you know that, if you can reduce the diameter of the bubbles in steamed milk by half, the liquid will drain out of the foam you create four times slower?
  2. What makes better foam — skimmed, semi skimmed, or full fat? Well, according to ( Kamath et al 2008 ), ‘Foams produced from skim milk and whole milk differ considerably in their appearance and bubble size distributions with whole milk foams showing smaller-sized bubbles and higher rates of bubble rupture as a result of coalescence during storage’. In other words, whole milk makes better foam for latte art and textural purposes, but it doesn’t last as long.
  3. Here’s one surprising stat which we expected to be much higher: Milk is approximately 87% water. It’s got more solids, both dissolved and undissolved,  in it  than a strong ristretto.
  4. In beverages with persistent foams, surfactants make bubbles less likely to burst because they reduce the surface tension between the liquid and the air. Low surface tension means more elasticity in a foam and elastic foams with low surface tension give the latte artist more time to pour while making the pattern last longer too. In milk, all that elastic magic comes from the whey protein called beta-lactoglobulin.
  5. Lastly, a particularly pertinent one, not only for the good of the planet, but also for your wallet: Research from 2013 suggests that 20% of the milk that reaches end users in the US goes to waste. At such high levels, this signifies gigatonnes of needless greenhouse emissions. It also indicates an opportunity for baristas to dramatically reduce the carbon footprint of their cafés. In this new video (this lesson is free to access), we outline a good system to help you calculate your café’s milk waste percentage and to get the number below 5%, at least. Even at 5% milk waste, that’s US$800 down the sink each year in a café producing 300 coffees a day.


New Films

We’re committed to bringing new films in every update to make all this info quicker and easier to digest. Check out these brand new films in the Milk Science course: MS 1.03 Pasteurisation , MS 1.07 Your Milk Waste Percentage and MS 2.04 Surfactants .


World Coffee Championships at Host

It’s competition week, folks! Check out the live stream here for the World Brewers Cup, World Barista Championships, and the World Cup Tasters. Good luck to all the national champions who have travelled to Milan this week.


Our Editorial Policy

At BH we never do ads for products on our website. There’s no product placement in any of our courses, newsletters or blog posts. Our only income comes from what you pay for your subscriptions. When you see machinery or coffee gear mentioned in any of our educational material, or featured in our course videos, we have chosen to use that equipment because we like using it or because it shows you something you need to see. It’s as simple as that.


As always, we're just an email away if you have any queries! Have great weekends and we look forward to seeing you next time.



To the Boundaries of Coffee,
Team BH

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