Dialing in Milk: But How?

I really enjoy a cortado. A delicate balance of espresso and steamed milk served in a small glass, no more than 4oz. It's one of the drinks that first got me excited about coffee. Fast forward about seven years when I began working with a cafe wielding the hashtag #teamcortado. Lucky to be able to focus almost 100% on coffee, I took the opportunity to dial the drink in as carefully as possible. Over the course of a few months, I became pretty obsessed.

 Anderson Coffee Works operations department ;)

Anderson Coffee Works operations department ;)

After a well dialed in shot measured by weight, the next variable was, of course, milk. What quickly became apparent to me was how much aeration effected the flavor of the drink. But it wasn't until I started measuring milk, by weight, that I realized just how large the effect was.

Below are three cortados I brewed at my home bar intentionally throwing off the balance by aerating 'heavily', 'moderately', and 'hardly at all'.

'You'll see why these words are in quotes.'

For the longest time, I thought that the way you aerated milk was mostly due to personal preference. A sort of personal mark for baristas to develop and to hone. It turns out that these variations lead to a wide distribution of coffee to milk ratios.

All of these drinks started with a 35g espresso yield. Depending on aeration, milk yield ranged from 35-72g! That's a espresso to milk ratio range of 1:1-1:2!! 

That's A Big Difference

The 'heavy' milk texture comes in at a ratio of 1:1. Espresso forward and rich. Easy to kick back and has a lingering finish.

A cortado with 'moderately' textured milk has more balance at 1:1.5. Sip slowly.

Last is 'hardly at all'. 1:2. It's hard to be objective with this one, super milky and sweet. It's a no foam cappuccino. 

I'm not here to debate which recipe is the 'ideal' recipe. All of these had their merits (well, maybe not the 'hardly at all' version). What's important is knowing the recipe you want to put out into the world and executing it every time.

This week I started testing whether or not this is worth worrying about in a cafe setting. While I don't have enough data to support the claim yet, early signs are pointing to yes. But more importantly than why we should be measuring this is how to do it. Cafes only recently started weighing espresso yields. Are scales for milk yields next? Can it be done with better volumetric milk measuring before and after steaming?

Give me a shout if you're in Baltimore and interested in throwing in some data. Looking for samples of espresso yield, by weight, and milk yield, by weight of drinks under 6oz during a cafe's normal operating hours from multiple baristas.