Group Head Gasket 58 mm – for Breville / Sage the Dual Boiler
The portafilter locks snugly back into the group, and the water takes the only path that counts: through the coffee. A group head gasket is a wear part. It hardens over the months, loses its springiness, and at some point water starts escaping sideways during the shot.
This version is made from white silicone and measures 70.8 mm on the outer diameter, 48 mm on the inner diameter and 8.8 mm in height. Silicone stays elastic across a wider temperature range than classic rubber and picks up less odour – that is our observation from the workshop, and others see it differently.
At a Glance
| Product type |
Group head gasket (brew group gasket) |
| Portafilter size |
58 mm |
| Outer diameter |
70.8 mm |
| Inner diameter |
48 mm |
| Height |
8.8 mm |
| Material |
Silicone |
| Colour |
White |
| Fits |
Breville / Sage the Dual Boiler |
| Weight |
10 g |
| Scope of delivery |
1 gasket |
Checking Compatibility
Confirmed by the supplier is the Breville the Dual Boiler. Breville and Sage are the same manufacturer: the Australian Breville Group sells its appliances in Europe under the name Sage, because the name Breville was already taken here by another company. The machines are structurally identical, the model numbers differ only in the prefix – BES overseas, SES in Europe.
Even so, the brand name alone is never enough for a reliable match. Measure your existing gasket and compare outer diameter, inner diameter and height. With 58 mm groups in particular there are many variants with similar but not identical dimensions.
Who It Is Made For
For everyone who keeps their machine in shape themselves and knows what to do at the first drop in the wrong place. The swap is a quick job with a slim screwdriver and a little patience – no workshop needed, no special tools. Whether your group sits on a machine that cost a few hundred or a few thousand francs makes no difference here: a tight group is a tight group.
If you are working on the brew group anyway, our machine and grinder cleaning range holds group brushes and cleaning powder for the backflush. Every day you backflush without any detergent, roughly every 50 shots with cleaning powder – that takes about five minutes and keeps the group seat clean, which lets every gasket live longer.
To match the 58 mm group we also carry IMS precision baskets for a more even extraction, plus tampers in two directions. For everyone who wants to tamp precisely and affordably: the pressure-regulating tamper from the Normcore Collection. If you want material, feel and finish on another level, you will find it at Weber Workshops. Both get you there – the decision is yours, and both paths are equally valid. More tools around the shot are in our barista equipment range.
Frequently Asked Questions
Does this gasket fit every Breville or Sage machine?
No. Confirmed is the Dual Boiler with its 58 mm group. The 54 mm models such as Barista Express, the Infuser, Bambino Plus or Duo-Temp need the smaller version with 65 mm outside and 49 mm inside. Always compare the dimensions of your old gasket before buying.
What are the exact dimensions of the gasket?
The outer diameter is 70.8 mm, the inner diameter 48 mm and the height 8.8 mm. The material is white silicone, the weight is around 10 grams.
How do I know the gasket is due for replacement?
Typical signs are water escaping sideways during the shot, a portafilter that has to be turned further and further to the left before it seats, and a gasket that feels hard instead of elastic. Coffee grounds on the rim of the group after the shot are another sign.
How is the gasket replaced?
Switch the machine off and let it cool down, loosen the shower screen, lever the old gasket out with a slim screwdriver, brush the group seat out thoroughly and seat the new gasket evenly. Locking in an empty portafilter helps to set it cleanly and flat.
Can I see the product before buying?
Yes. You will find us in Bern at Gerberngasse 44 and in Zurich at Hagenholzstrasse 50b, with the larger showroom and the roastery in Zurich. Ordered online, we deliver within 2–4 working days across Switzerland and to Liechtenstein.
Not sure whether the dimensions match your group? Write to us at [email protected] or call us during business hours – we will look at it together. Everything else is on coffeecoachingclub.ch.
From the Roastery
A fresh gasket noticeably changes the way pressure builds – a good moment to dial the recipe in again. We go by the weight ratio, for us usually below 1:2, never by time alone. For the great majority, Cozy Chocolate and Nutty Delight are the dense, full-bodied companions for that. If you are after maximum body without any acidity, take Very Nutty. And if you are curious about a fruity experience, you will find it in Wild Peach. That is our recommendation, one of many – every bean works.
