Good day to all of you and thank you for engaging so openly with the launch of Slayer Steam. I’m Sarah Dooley and I work primarily in Marketing at Slayer, although R&D is where I’ve spent the last 6 months learning and testing.
Let me begin by saying that we recognize there are a lot of questions. Our research has produced solid answers, but we will conduct further tests if we come up short in any conversation. You all deserve the truth.
I want to take this one topic at a time, starting with dry steam / dilution.
The core technology inside of Slayer Steam is a compact super-heater, which we call the Vaporizer. As steam leaves the boiler, it passes through the Vaporizer and is flash-heated at high temperatures to remove water, resulting in a dry vapor. Our steam tank is usually set to around 250º F; the Vaporizer is much hotter, producing steam that registers at 360º F. (That's the output temperature, not the element setting.) Compare this with a conventional system, which produces steam that registers around 212º F at the wand.
The result is a drier steam that is nearly invisible. Counter-intuitively, perhaps, drier steam results in slower heating because the liquid water in conventional systems actually helps to transfer heat. When compared to Slayer Espresso, Slayer Steam takes 3-4 seconds longer to bring 150 mL of whole milk to 130º F.
So, this dry steam uses less liquid to heat milk. This brings us to the topic of dilution. Simply put, we don't "water down" milk as much as most machines do. Conventional systems add an average mass of 10% liquid water back to the milk. Slayer Steam averages 6.5%. Does a difference of 3.5% really matter? We think so.
SCAA and SCAE Gold Cup Brewing Standards tell us there is a preferred flavor experience window that is just around 19-22% extraction. That’s a window of 4%. Swing that pendulum just 3.5% under or over and you can write yourself out of winning the brewers cup or, for what it’s worth, hitting the masses where their palates want flavor to be.
You can taste the difference with a simple test: heat two airtight bags of milk via sous vide, then dilute one with 3.5% of its mass in water. Similarly, anyone who enjoys scotch (like me) will note that adding just a few drops of water to a very complex scotch will change the experience completely.
We will be the first to say that we did not make all of these conclusions on our own. Over the last few months, we employed three outstanding food and coffee professionals to make sure that we weren't "drinking our own Kool-Aid". We believe that these are real changes, which will make a real difference to our guests cup experience.
Thanks for participating in this with us; more info is coming soon. For now, let's keep talking about dry steam and dilution!