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I was wondering why a portafilter coffee machine takes up to 15 minutes to warm up in order to make an espresso.

On the other side, a modern Nespresso Citiz doesn't even take a minute to warm up.

What makes the difference here?

Aaronut
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Johannes Schaub - litb
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2 Answers2

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By portafilter I assume you mean the standard large coffeeshop espresso machine.

The Nespresso is only heating enough water for a single shot, which can be done pretty quickly. I'm pretty sure commercial machines take a long time for that first shot because they're preheating the large reservoir so it's possible to fully heat and pull shot after shot in fairly quick succession once you get going.

So the lag is because the bigger machine is heating a bunch more water--even if it doesn't superheat any more per shot than the Nespresso.

Somebody correct me if I have this all wrong, but that's what I was led to understand.

bikeboy389
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    I think you also have to consider everything else that has to heat up. I know I preheat my Rancilio Silvia for 45 mins to an hour to increase temperature stability when pulling the shot, the water heats up probably in 10 minutes but all that brass at the group has to heat up too as well as everything along the brew path. Even with the added PID on my machine I like to give it a good solid 45 minutes to reach stability. Have a look at this thread http://coffeegeek.com/forums/espresso/machines/444952 – C.Trauma Jun 22 '11 at 20:00
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It'll depend on how much stuff you need to warm up to maintain acceptable thermal stability. In a typical machine, you will have a brass boiler, attached to huge chunk of metal that the portafilter fits into,the grouphead.

http://en.wikipedia.org/wiki/Grouphead

The water in the boiler will probably heat up pretty quickly. However your grouphead and basket will still be cold. If you pull a shot now, you'll lose heat to the surrounding mass. This is no good when you are trying to maintain a particular temperature.

15 minutes is probably too short to wait though. I am waiting at least 30 minutes on my domestic machine with an E61 grouphead.

If you look at a Nespresso machine, well there is not much machine. The ones I have seen are kinda plastic-y as well. So not only are the internal water paths very compact, but they wrap the entire thing in an insulator. Probably pretty efficient.

Megasaur
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