WPM Primus – Espresso Machine with Pressure Profiling

WPM Primus – Espresso Machine with Gear Pump and Pressure Profiling

The milk starts swirling the moment the wand dips in. A quiet, even hiss, the vortex draws air into the finest pores, and within seconds the foam gleams like freshly poured cream. At the same time, the espresso runs alongside – golden brown, dense, with the machine never having to choose between the two. That exact side-by-side is the moment the WPM Primus was built for.

A gear pump changes what you taste

Most machines for home use run a vibration pump: pressure comes as it comes. The Primus instead relies on a gear pump – quiet, even and, above all, controllable. Adjust extraction pressure in real time, watch the pressure curve live on the colour display, and save your own profiles or pick one of the presets.

Why that changes the taste comes down to extraction chemistry: different compounds dissolve at different points in time, and pressure shapes that aromatic window. A gentle pre-infusion lets the grounds swell evenly before full pressure draws out sweetness and body – caramel and chocolate step forward, harsh notes fall away. Coffee contains over 800 compounds, and the pressure profile is part of what decides which of them end up in your cup. It's a learning process, not a push-button promise – and that's exactly what makes it exciting. If you'd rather pull a constant shot, you can just run the Primus the classic way. Both paths are valid, and our opinion on this is one of many.

Three heating circuits, one goal

Inside works a hybrid system: a 0.8-litre boiler for thermal stability, a PID-controlled thermoblock for brew temperature, and a separate SuperSteam thermoblock just for steam. That means pulling espresso and steaming milk at the same time – no switching, no temperature drop. Brew temperature is adjustable from 70 to 98 °C and stays stable within ±1 °C. Temperature helps decide which compounds dissolve: higher for more body, lower for more complexity – the Primus hands you that range built in.

The thermoblocks heat on demand, with fresh water on every shot. Our practical recommendation: give the machine at least 10–15 minutes to warm up, until the brew group and portafilter are heated through too – the espresso then tastes noticeably rounder.

Steam made for latte art

WPM comes out of the latte art scene, and you can feel it in the steam: it's powerful, continuous and known in the community for its dry character. The 360° steam wand with a two-hole tip and seven adjustable steam levels brings the milk into a rolling texture right away – fine-pored, glossy microfoam that holds hearts, tulips and rosettes. With a pitcher from our Milk Pitcher Collection you have exactly the right tool in hand for it. Latte art is a matter of practice, and consistent steam helps with that more than any talent.

At a glance

Who is the WPM Primus for?

For everyone who loves milk drinks – cappuccino, flat white, latte – and doesn't want to give up espresso quality for it. For everyone who wants to understand how pressure shapes taste, and enjoys playing with profiles. At just 23.5 cm wide, it fits on narrow kitchen counters too – though it does need some depth.

Nobody needs a Primus. It's something you want – for the control, for the steam, for the feeling that comes when the pressure curve on the display follows your hand. That decision is emotional, and we respect it either way. If you're unsure which type of machine suits you, our machine comparison tool can help – or you can experience the Primus live in Bern (Gerberngasse 44) or Zürich (Hagenholzstrasse 50b).

What goes well with it

A machine is only as good as the grinder next to it. For everyone who wants precise, affordable grinding: the VS3 from our Varia Collection. If you want maximum grinding quality: the EG-1 from the Weber Workshops Collection. The same principle applies to weighing – compact and reliable with a scale from the Normcore Collection, or with an app and flow-rate display from the Acaia Collection. It's your call – no budget is ever just a starting point.

When you buy a machine over CHF 1500, a private barista course in Bern, Zürich or online is included – a session covering extraction philosophy and your espresso ritual. Financing available. Delivery in 2–4 business days, across Switzerland and to Liechtenstein.

Frequently asked questions about the WPM Primus

Is a thermoblock system worse than a boiler?

The Primus is both: a 0.8-litre boiler provides thermal stability, and two thermoblocks heat on demand. The result is a brew temperature accurate to ±1 °C and fresh water on every shot. Boiler and thermoblock are different paths to the same goal – neither is the only right one. We recommend giving the machine at least 10–15 minutes to warm up, so the brew group and portafilter are up to temperature too.

Can I pull espresso and steam milk at the same time?

Yes. The SuperSteam thermoblock is dedicated solely to steam, leaving the brew circuit unaffected, so you work as you would on a commercial machine – no switching, no waiting between espresso and milk.

Is Pressure Profiling complicated?

No. The Primus can be run at constant pressure just like any classic machine. If you want to dig deeper, pick a preset profile or build your own – for example with a gentle pre-infusion before the main extraction. We extract by weight ratio, 1:2 as a starting point, and adjust the profile to the taste, never the other way around.

Which grinder suits the WPM Primus?

Any single-dosing grinder with an espresso-fine grind. Affordable and precise: the VS3 from the Varia Collection. If you want more: the VS6 or a grinder from the Weber Workshops Collection. An overview is available in our Coffee Grinders Collection.

Can I see the WPM Primus before buying?

Yes, gladly. Find us in Bern at Gerberngasse 44 and in Zürich at Hagenholzstrasse 50b. Come by, experience the steam live, and pour a heart with us. Order online any time via coffeecoachingclub.ch – for questions, reach us at office@coffeecoachingclub.ch or by phone during business hours.