In which cases do you use Wasser siedet and when Wasser kocht? It looks like the two aren’t synonyms.

6 Answers 6


Sieden is a scientific term, describing one of the two variants of the change of a liquid to a gas. The variant sieden describes the variant, where the vapor pressure is at least the surrounding pressure. In that case, gas bubbles develop inside the liquid, which then go up the liquid. (The other variant is verdunsten which happens if the vapor pressure is below the surrounding pressure.)

This term is rarely used outside of science or scientific applications.

Kochen is not a scientific term, but a cuisine term. In the case of water it describes very hot water. In traditional, european cuisine, this means sieden. But there are modern cuisines or cooking techniques which employ hot water below boiling temperature.

  • 1
    @Stephie OK, it's called simmern and pochieren. Changed the answer.
    – Toscho
    May 17, 2015 at 17:28
  • @Jan Ok, changed it.
    – Toscho
    May 26, 2015 at 15:27

When I was young my grandmother told me that water siedet at around 90° – when you see the first bubbles (even though, scientifically that’s not correct. Maybe in cooking it’s working somehow). But I can't remember I ever used that term except in chemistry.

Once I was told there are some ideas to tie the chemists’ words closer to the spoken language. But I guess there are more people who use sieden instead of kochen than Kochpunkt instead of Siedepunkt. (Or Frierpunkt)

  • you talk about "sieden" as soon as you see the bubbles. you are right. "Sieden" starts before "kochen" , kochen is from 100°C+ and "sieden" is before 100°C . May 12, 2014 at 15:27
  • Chemically you can't really boil water with more than 100°C. Basically in Austria you can't even reach 100°C (I live in a town about 600m above sea level). Here it starts to boil at around 96°C. I think some teas refer to use siedendes water so it does not destroy the fabric of the bag.
    – Qohelet
    May 12, 2014 at 15:37
  • 3
    Is that "Frierpunkt" you are talking about standard "Österreichisch". From Germany I only know "Gefrierpunkt"
    – Vogel612
    May 12, 2014 at 15:49
  • Nobody says "Frierpunkt" this was more an ironic referrer to words which exist per definition but are hardly used
    – Qohelet
    May 12, 2014 at 21:29
  • 2
    Frierpunkt sounds as if the water is just about to catch a cold.
    – bot47
    May 14, 2014 at 20:44

In modern everyday language one says Wasser kocht bei 100 Grad. Sieden has come out of use in normal language, its use in scientific areas has already been mentioned above. But members of the word family are still around. We speak of Siedepunkt und Gefrierpunkt des Wassers and of Tauchsieder or we say Er ist ein hartgesottener Bursche. Historically we can find Salzsiederei or Seifensieder or in older texts gesottenes Fleisch, Gebratenes und Gesottenes.

By the way the stem forms can be:

sieden, siedete, hat gesiedet or
sieden, sott, gesotten

sieden in DWDS
In DWDS I’m missing the hint that sieden has come out of use in modern everyday language.


Der Siedepunkt ist jene Temperatur, an dem Wasser vom flüssigen in den gasförmigen Zustand übergeht. Das passiert zunächst in der Nähe der Wärmequelle, also am Boden des Topfes: Wasser wird gasförmig und steigt (durch das noch flüssige Wasser) auf, es siedet. Von kochen spricht man erst dann, wenn das gesamte Wasser diese Temperatur erreicht hat, und wallt.

Der Unterschied ist im Alltag belanglos. Chemiker sprechen immer von sieden (nie kochen), in einem Kochrezept ist siedendes Wasser sehr heiß, aber gerad noch nicht vollkochend.

  • I as a chemist usually say unter Rückfluss erhitzen rather than sieden or kochen. If anything, I use the Siedepunkt in the lab.
    – Jan
    May 17, 2015 at 18:31

I rarely use das Wasser siedet. I know what it means but colloquially in my area (Thuringia) we say das Wasser kocht. You can say das Wasser zum sieden bringen. But again where I’m from that is rare. See the other answers for the definition of sieden.

Based on these you can use sieden as a reference point during cooking. It is earlier than full on boiling. Sieden would be the equivalent of boil in english according to Google translate. Though I myself would rather say it compares to simmer. Which is cooking but not at full heat.


Appliance: Wasserkocher

Temperature: Siedepunkt

Action: Wasser zum kochen bringen.

State: Das Wasser hat die Siedetemperatur/Siedpunkt erreicht.

State: Das Wasser kocht.

State: Die Milch kocht über.

State: Die Suppe muss auf mittlerer Hitze köcheln. (close to the Siedepunkt but not full power)


The difference between the two is that nobody uses das Wasser siedet and you can use it only if the water is above 100 degrees Celsius.

  • Sorry for my bad english, I'm from germany ;)
    – TechRobin
    May 12, 2014 at 14:59
  • 4
    yes and it's not correct ;) May 12, 2014 at 15:25
  • Ok could be possible. Thanks for saying that :)
    – TechRobin
    May 12, 2014 at 15:38
  • 1
    "sieden" is commonly used as a scientific term in Chemistry, so to say "nobody uses" it would be wrong. I also think @Toscho is right with the distinction between "sieden" and "kochen" being a scientific and a cuisine term, rather than a difference in temperature.
    – Kodama
    May 12, 2014 at 17:13

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