According to “A Series of Tubes” by Molly Wright Steenson:

If a pneumatic canister got stuck and couldn’t be cleared by reversing airflow, there was another solution: firing a pistol into the tube line, which created a sound wave that traveled at 330 meters per second to the point where the tube was obstructed. A chronograph and recording cylinder marked the distance, making it possible to find the obstruction within two meters and access it through the sewer. It was a better but perhaps less festive solution than in Berlin, where frozen pneumatic tube canisters would be loosened by pouring copious amounts of wine into the tubes.

I checked out Rohrpost in Berlin on Wikipedia and the German version thereof, but neither seems to mention wine. So, was wine used for clearing out frozen tubes in the system?

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    How is using wine even supposed to help? First, if you have pneumatic tubes, pouring liquid into them doesn't seem like a good idea in general. Second, even if you do that, why use wine instead of water? Seems highly implausible to me.
    – quarague
    Commented Nov 22, 2023 at 11:41
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    @quarague: I interpreted it as: the tubes iced up in the German winter, causing the cannisters to get blocked. The alcohol in the wine acted like anti-freeze. [I am not vouching for the veracity of this, just clarifying what I think the claim is.]
    – Oddthinking
    Commented Nov 22, 2023 at 12:46
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    @Oddthinking: Indeed, if you pour water into a frozen pipe, you're just going to get it more clogged with ice. Alcohol will lower the freezing point and melt the ice. And from Laurel's answer, it seems that the liquid used wasn't actually wine, but more likely just industrial alcohol, which would work much better due to its higher concentration. Commented Nov 22, 2023 at 19:09

2 Answers 2


Landrath, "Die Rohrpost-Anlage in Berlin und Charlottenburg." Archiv für Post und Telegraphie , Vol. 16, No. 12, Jun. 1888, pp. 354-369 describes, among other items, the initial version of Berlin's pneumatic post system. This was built by Siemens & Halske and became operational on November 18, 1865. On page 358, he discusses a major design flaw (bolding mine; otherwise all of the original spelling and typography have been retained):

Ein wesentlicher Fehler in der Ausführung bestand darin, daſs die Röhren nicht überall in ausreichender Tiefe unter dem Pflaster lagen. In Folge dieses Umstandes kam es sehr häufig vor, daſs bei Pflasterungen der Straſsen, Instandsetzungen und Neuanlagen der Gas- und Wasserleitungen u.s.w. die Röhren von Arbeitern mit der Hacke angehauen wurden, was vielfach Entstellungen des Querschnittes der Röhren und damit Störungen im Betriebe zur Folge hatte. Aus der gleichen Ursache wurde im Winter, oft bei nur wenige Tage anhaltender strengerer Kälte, der Betrieb durch Eisbildungen in den Röhren nicht selten Tage lang gestört. In solchen Fällen wurden zur Ablösung des Eises von den Rohrwänden verhältniſsmäſsig groſse Mengen flüssigen Weingeistes in die Röhren eingeführt. Das losgelöste Eis wurde durch einen mittels erhöhten Druckes zum Oefteren durch die Rohrleitung hindurchgetriebenen, mit Bürsten besetzten Kolben nach und nach aus den Röhren beseitigt.

My translation: "A substantial defect of the installed system was that the tubes were not always laid at sufficient depth below the pavement. As a consequence of this circumstance it happened frequently that during the paving of streets, the repair and new installation of gas and water lines, etc., the pipes were damaged by workers with hoes, which lead to frequent distortion of the cross section of the pipes, resulting in service outages. For the same reason operations were disrupted during winter, frequently after just a few days of continuous severe cold, by ice forming in the tubes. In such cases relatively large amounts of spirits of wine were introduced into the tubes to detach the ice from the tube walls. The dislodged ice was then gradually removed from the pipes by a brush-studded piston that was repeatedly driven through the line with increased pressure."

For the translation of "Weingeist", I relied on William James, A Complete Dictionary of the English and German Languages, Leipzig: B. Tauchnitz 1882, to accurately capture the sense of the word at the time of the publication above. As other answers have pointed out, spirits of wine refers to a mixture of ethanol and water; the product of distillation.

Other literature I consulted (see list below) does not mention this particular method of cleaning. It therefore seems likely that the above publication is the origin of the information cited in the question and that at some point someone confused spirits of wine with wine. I note that descriptions of the pneumatic post system in Berlin after it became available to the general public in 1875 point out that the air introduced into the tubes is cooled and dehumidified to prevent the formation of ice which is of particular importance as the extended system utilized various bridges where the tubes were directly exposed to the air.

Pennrich, "Die Rohrpost-Einrichtungen in Berlin." Archiv für Post und Telegraphie, Vol. 4, No. 23, Dec. 1876, pp. 705-714

Hellwig, "Pneumatische Erscheinungen beim Rohrpostbetrieb." Archiv für Post und Telegraphie , Vol. 6, No. 10, May 1878, pp. 289-301

Grose, "Beschreibung der Rohrpostanlage in Berlin." Der Bär. Illustrierte Berliner Wochenschrift, Vol. 6, 1880, pp. 92-96

O. Veredarius, Das Buch von der Weltpost. Berlin: Herm. J. Meidinger 1885. "Rohrpost", pp. 197-203

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    The Postrath Landrath document seems to be the German source that the American sources in the other answers rely on - couldn't google it for the life of me, even now, having the original, i cannot get Google to show it. how did you find it? did you search directly in books.google?
    – bukwyrm
    Commented Nov 23, 2023 at 16:21
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    @bukwyrm I went straight to Google Books to search for "Berlin" + "Rohrpost" restricted to the years 1860 to 1900. I have had much practice searching German publications from answering questions on History Stack Exchange and History of Math and Science Stack Exchange. Even so, it took me several hours of searching and cursory reading to find the relevant publication.
    – njuffa
    Commented Nov 23, 2023 at 20:33

Annual report of the Postmaster General, 1891 is as close to a primary source as I could find:

In working the line of Berlin tubes a number of defects became apparent in course of time, caused partly by the insufficient execution of the system, and partly by the unsuitable arrangement of the different portions. One of the most noticeable defects was this, that the tubes had not been laid at a sufficient depth under the pavement. It consequently happened frequently that during the repavement of strects, the laying of gas and water pipes, etc., the workmen injured the tubes with their pick-axes, thus disturbing the working of the system. Owing to the insufficient depth at which the tubes had been laid, ice formed in the tubes during periods of severe cold, and the working was frequently interrupted for days. In such cases large quantities of liquid spirits of wine were introduced into the tubes for the purpose of detaching the ice from the walls of the tubes. After the ice had been detached, it was gradually removed from the tubes by passing (by means of largely increased pressure) a piston with brushes through the tubes.

The paragraph that follows this gives the implication that this took place in 1866, in the very first years of the system, but it's not entirely clear; "in course of time" could mean a number of years later. On one hand, the vague potential gap of 25 years makes it less credible, but you'd also expect the Postmaster General to know something about the post.

This is the earliest example I can find of the claim in English sources, but German sources may bear more fruit.

By the way, Encyclopedia Britannica 1911 defines "spirits of wine" as ethanol, not an alcohol fit for consumption:

Commercial alcohol or "spirits of wine" contains about 90% of pure ethyl alcohol, the remainder being water.

  • 53
    An important note here is that the term is not just wine, but spirits of wine. That's an old-fashioned generic term for distilled ethyl alcohol. We're not talking about pouring a barrel of Riesling down the pipes; more like an industrial solvent. "Spirits of wine" needn't come from wine at all, nor be drinkable; it just identifies the chemical substance. Commented Nov 22, 2023 at 18:59
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    So perhaps the Missouri Review author read this report, or something similar, but misunderstood it, and wrote "wine" instead of what a modern audience would just call "alcohol". Commented Nov 22, 2023 at 19:04
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    @NateEldredge The American author might have been relying on a prohibition-era source which refused to admit the existence of anything stronger than small beer. Commented Nov 23, 2023 at 7:47
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    @GEdgar: Yes, and more importantly the freezing point of ethanol–water mixtures is significantly lower than that of pure water, so water ice will dissolve in liquid ethanol even below 0 °C. Commented Nov 23, 2023 at 11:44
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    Maybe worth noting that a number of liquids had 'spirits of...' or 'spirit of...' common names which may be thought obsolete now: of hartshorn (aqueous ammonia), of nitre (nitric acid) of salt or salts (hydrochloric acid), of vitriol (sulfuric acid), of nitrous ether (ethyl nitrate), of copper (acetic acid obtained by distilling copper acetate), of vinegar (acetic acid more generally). Commented Nov 24, 2023 at 16:11

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