My Stelton EM77 vacuum jug cap ball hack

Don’t ever try to do this hack after me. It may cost you(r wife) broken ceramic cups and a spoilt tablecloth. I haven’t even tested it myself. But it may be fun to read. New 08Apr2023. Updated 08May2023 (COOL-IT, Rig-tig). In group Hobby.

Since everybody seem to have have this nice Stelton EM77 (‘EM’ after its designer Erik Magnussen who designed it in 1977) vacuum jug, I have wondered why it seems that on too many occasions I’ve seen it used, its cap falls off and spoils coffee all over the place. At tablecloths, at my white shirt or my wife’s dress. Or somebody else’s. Because it has not always been me who have failed so miserably.

I have no idea why this seems to happen. Studying the EM77 design it should be impossible. The rocker stopper’s lock and opening mechanism looks rock solid by design. Is it that the picnic cap is used instead, and we think that it sits in position, like the rocker stopper would have? I have no statistics on this (*). On the photos above I have placed a flashlight inside the jug. Luckily it was empty enough not to destroy the sensitive electronics in the torch. I taped some foam plastic on the rocker stopper’s arm so I could force it to a a somewhat open position so that (5) could be shot. (6) shows the alternative picnic cap in a somewhat open position.
(*) Update: When I double checked with a person who has experience with a lot of coffee occasions with a couple of EM77 present, she said she had not noticed any trouble with them. Hmm..

I thought, what could the problem be? Provided there is a problem. Might it be that the (so far) happy pourer is stressed by its long design and waits for the coffee to appear at some angle, and then just don’t realise that the cap (or stopper, (which I do doubt)) is bound to fall off? I found a 45 mm compact bouncing ball in a toy store (*). I think a 50 mm ball would be too large; it would collide with the pin that holds that caps. Filling the bottle with tap water and turning it upside down, pressing the ball upwards, the water was indeed kept above the ball. Maybe, in upright position, as any coffee gets colder, the ball may be sucked in, so that it will sit too firmly? As I said, I haven’t tested it in real life. And I am not certain if I would be allowed to, if I asked. Or if I would be bold enough to take the responsibility all on myself.
(*) Made from “polybutadiene rubber, calcium carbonate and mineral oil” according to the manufacturer – with no guarantee that it is suitable for food.

If the problem, to repeat myself: if any problem at all – if that problem is not technical, but rather along a cognitive axis: that the pourer does not recognise the situation, which then some times causes havoc around the coffee table, then perhaps a ball is recognised, is seen, or feared as something that must immediately be removed before the jug is even lifted? What, a ball – there? Get it off! Then a grip to get it off, to be held with the other hand, and when the situation is open and free of angst, the coffee is nicely poured from the long jug to the cups around the table. Then the jug is set aside, and the ball, still in that hand, must be placed somewhere. Like (where else?) on the top of the jug, so that the rest of the coffee is kept warm as it should. As I said, I haven’t’ tested this in vivo, this is a pure desk design. Even if I did find a good ball in that shop. And a handle for it in one of my haberdashery boxes in my shop; from some bottle that was broken. The proud EM77 has been field tested for 46 years. So who am I, who even dare challenge it, even with a potentially rather dead idea. But wow, have I had fun!

Aside. According to the Swedish Wikipedia page (which strangely has more about this than the Danish) then “From 1976, Magnussen also worked for Stelton A/S in Copenhagen. There he designed the elegant and timeless one liter 30 centimeter high thermos EM77 in colorful ABS plastic, which is still in production and has become one of the company’s best sellers. This thermos was originally intended to complement Arne Jacobsen’s Cylinda-line metal collection from 1967.” (Google translate). Later on, at some time, Stelton decided to go for a stainless steel version of the EM77, making the Jacobsen complement complete, I assume.


I have discovered a ball cap, from Stelton! It’s on the COOL-IT carafe 1.5 l, in their Rig-tig line. It’s designed by the Canadian Francis Cayouette at UNIT 10 design for Stelton: “The carafe sports smart open-and-close detailing – just flip the ball down for pouring and then up again to seal the carafe.” The ball and connection to a collar rubber band which fits around the neck of the bottle makes it not possible for the ball to fall off. All is cast as a single piece of rubber. It may be force-dismantled for washing, but that function is unclear to me.


Wiki-refs: Swedish: Arne Jacobsen, Erik Magnussen,

  1. EM77 vacuum jug 1 l. at the Stelton site

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