WPM Primus – Espresso Machine with Pressure Profiling

WPM Primus – Espresso Machine with Gear Pump and Pressure Profiling

The milk starts to swirl as soon as the wand enters it. A soft, even hiss, the vortex draws air into the finest pores, and after a few seconds, the foam gleams like freshly poured cream. At the same time, the espresso is brewing next to it – golden-brown, dense, without the machine having to choose between the two. This simultaneous operation is precisely the moment for which the WPM Primus was built.

A Gear Pump Changes What You Taste

Most home machines use a vibration pump: the pressure comes as it comes. The Primus, on the other hand, relies on a gear pump – quiet, even, and above all, controllable. You regulate the extraction pressure in real-time, see the pressure curve live on the color display, and can save your own profiles or choose from one of the preset ones.

Why this changes the taste lies in the chemistry of extraction: different compounds dissolve at different times, and pressure shapes this aromatic window. A gentle pre-infusion allows the coffee grounds to swell evenly before full pressure brings out sweetness and body – caramel and chocolate come to the forefront, harsh notes remain. Coffee contains over 800 compounds, and with the pressure profile, you help decide which ones end up in your cup. This is a learning process, not a push-button promise – and that's what makes it so exciting. If you prefer consistent brewing, simply run the Primus conventionally. Both approaches are valid, and our opinion is just one of many.

Three Heating Circuits, One Goal

Inside, a hybrid system works: a 0.8-liter boiler for thermal stability, a PID-controlled thermoblock for brewing temperature, and a separate SuperSteam thermoblock solely for steam. This allows simultaneous espresso extraction and milk frothing – without switching, without temperature drop. The brewing temperature is adjustable from 70 to 98 °C and remains stable at ±1 °C. Temperature helps determine which compounds dissolve: higher for more body, lower for more complexity – the Primus gives you this freedom.

The thermoblocks heat on demand, with fresh water for each shot. Our practical recommendation: allow the machine at least 10–15 minutes of warm-up time until the brew group and portafilter are also thoroughly heated – the espresso will then taste noticeably smoother.

Steam Made for Latte Art

WPM comes from the latte art scene, and you can feel it in the steam: it's powerful, continuous, and known in the community for its dry characteristics. The 360° steam wand with a two-hole nozzle and seven adjustable steam levels immediately puts the milk into the rolling phase – fine-pored, shiny microfoam that supports hearts, tulips, and rosettas. With a pitcher from our Milk Pitcher Collection, you have the right tool in hand. 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-based drinks – cappuccino, flat white, latte – and doesn't want to compromise on espresso quality. For everyone who wants to understand how pressure shapes taste and enjoys experimenting with profiles. At just 23.5 cm wide, it fits even on narrow kitchen counters – though it needs depth.

No one needs a Primus. You want it – for the control, for the steam, for the feeling that arises when the pressure curve on the display follows your hand. This decision is emotional, and we respect it in both directions. If you are unsure which type of machine suits you, our coffee machine comparison will help – or you can experience the Primus live in Bern (Gerberngasse 44) or Zurich (Hagenholzstrasse 50b).

What Goes Well With It

A machine is only as good as the grinder next to it. For those who want to grind precisely and affordably: the VS3 from our Varia Collection. For those who want maximum grind 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, with app and flow rate display from the Acaia Collection. The customer decides, no budget is just an entry point.

When purchasing a machine over CHF 1500, a private barista course in Bern, Zurich, or online is included – an encounter centered around extraction philosophy and your espresso ritual. Financing possible. Delivery in 2–4 business days, throughout 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-liter boiler ensures thermal stability, and two thermoblocks heat on demand. The result is a brewing temperature accurate to ±1 °C and fresh water with every shot. Boilers and thermoblocks are different paths to the same goal – neither is the only right one. We recommend giving the machine at least 10–15 minutes of warm-up time so that the brew group and portafilter are also at temperature.

Can I extract espresso and froth milk simultaneously?

Yes. The SuperSteam thermoblock is exclusively responsible for steam, leaving the brewing circuit unaffected. You work as if on a commercial machine – without switching, without waiting time between espresso and milk.

Is Pressure Profiling complicated?

No. You can run the Primus with constant pressure like any classic machine. If you want to delve deeper, choose a preset profile or create your own – for example, with 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 is suitable for the WPM Primus?

Any single-dosing grinder with an espresso-fine grind. Affordable and precise: the VS3 from the Varia Collection. For those who want more: the VS6 or a grinder from the Weber Workshops Collection. You can find an overview in our Coffee Grinder Collection.

Can I see the WPM Primus before purchasing?

Yes, gladly. You can find us in Bern at Gerberngasse 44 and in Zurich at Hagenholzstrasse 50b. Come by, experience the steam live, and pour a heart with us. You can order online anytime at coffeecoachingclub.ch – for questions, you can reach us at office@coffeecoachingclub.ch or by phone during business hours.