Baudoinia compniacensis

Learning about Baudoinia compniacensis was the prompting for a “Botany and Spirits” series, as the story intrigued me so much. A big thank you to Dr. James Scott, Associate Professor from the Dalla Lana School of Public Health at the University of Toronto for sharing the first three images, and a nod of appreciation to Shadle@Wikimedia Commons for a photograph of the phenomenon caused by the organism at Heaven Hill Distillery in Bardstown, Kentucky, USA.

Baudoinia compniacensis is known commonly as the angels’ share fungus or warehouse staining mold. When distilled beverages are aged in wooden barrels, a portion of the liquid is lost to evaporation through the pores of the wood. For a spirit like rum which is distilled in tropical and warm temperate regions, the loss can reach (exceed?) 10% annually, whereas spirits aged in colder climates might lose 1-2%. The alcohol “lost” due to evaporation is called “the angels’ share”.

A decade or so ago, Dr. Scott was contracted by Hiram Walker Distillery in the community of Lakeshore, Ontario to determine whether a mysterious black mold blanketing local buildings and objects (including stainless steel fermenter tanks!) had anything to do with the distillery. Previous attempts by other researchers were either explained away as typical environmental fungi or recognized as a biological stumper. Dr. Scott immediately suspected something different than the typical, and started to track down fungi associated with ethanol. After discovering how to isolate and culture the fungus (the photographs above from Dr. Scott), he began to compare it with other fungi. His initial investigations led him to examine Zasmidium cellare, the cellar fungus, which grows in caves and cellars used for aging wines–but this had to be rejected because it was both different in morphology and grew in a very different environment. Researching in the mycology collections of the National Herbarium of Canada, he and Stan Hughes came across a sample of Torula compniacensis collected from Cognac, France (compniacensis = of Cognac) in the late 19th century. It closely resembled the sooty black mold from Ontario.

Via a colleague, a living sample from Cognac was obtained by Dr. Scott; it was cultured and proved to be a match. But, it didn’t yet have a valid name, as Torula was used for many years as a sort of placeholder genus for different species and genera of black molds, most of which have now been split into separate genera. Torula is now restricted to a very well-defined set of characteristics, and this species did not conform. A new genus was necessary, and so Baudoinia was put forth in 2007 (see: Scott, JA et al. 2007. Baudoinia, a new genus to accommodate Torula compniacensis. Mycologia. 99(4): 592-60. doi: 10.3852/mycologia.99.4.592 ).

The genomic sequence for Baudoinia compniacensis has been completed and the species is described on the Joint Genome Institute’s site: Baudoinia compniacensis. Quoting from the site: “The extremophilic sooty mold Baudoinia compniacensis is the prominent pioneering species in the primary successional community known as “warehouse staining”, where darkly pigmented microbes form dry biofilms on outdoor surfaces periodically subjected to low level exposure to ethyl alcohol vapour, such as those around distilleries, spirit maturation facilities (“bond warehouses”) and commercial bakeries. Pronounced blackening often extends considerable distances from alcohol emission source, indiscriminately colonizing exposed surfaces ranging from vegetation to built structures, sign posts and fences (including those made from glass and stainless steel). Mature colonies are crust-like and scorched in appearance, sometimes reaching 1–2 cm in thickness”.

For a longer version of this story about Baudoinia compniacensis (and where I learned about it), please read the Wired magazine article by Adam Rogers: “The Mystery of the Canadian Whiskey Fungus“. It goes into far more detail than I can in this space, and Adam Rogers knows how to tell the tale.

I find it fascinating that this broadly-distributed organism (it is found around the world wherever distilleries are located) lacked a valid name until the 21st century, and that it was a mystery to many for such a length of time (despite its prominence in areas where it grows). Also intriguing is that it is yet to be seen in nature, where presumably it grows in small colonies associated with naturally-occurring fermentation processes (e.g., rotting fruit). It also is a strong reminder of the importance of well-supported herbaria; had there not been samples of the original collection from France in the National Herbarium of Canada, who can say how the story would have evolved. Fortunately, with the resampling and renaming, new specimens have now been deposited into collections worldwide such as the Microfungus Collection and Herbarium at the University of Alberta.

Additional photographs of this species and examples of “warehouse staining” are available via Wikimedia Commons: Baudoinia compniacensis.

Baudoinia compniacensis
Baudoinia compniacensis
Baudoinia compniacensis
Baudoinia compniacensis

14 responses to “Baudoinia compniacensis”

  1. quin ellis

    Nicely done Daniel, thank you. It IS amazing that for all of these years of studying something that is important to many (perhaps as part of an egg nog from scratch) that we ‘just now’ have it named! What next? Holiday greetings!

  2. Richard Jaffe

    This story reminded me of the ‘discovery’ of Spinosad, an insecticide that derived from a microorganism that lives in the soil around an abandoned rum distillery (check out for more details). It was discovered by a vacationing microbiologist in Jamaica, who brought soil samples home and isolated the organism. This case, however, may be one of an organism unique to that particular distillery.

  3. Martha

    When I first scrolled down I thought that was painting on the building. It may be an undesirable but it makes art. Great post.

  4. brian

    At long last i find out the name of this fungus – thank you!
    In the Cognac region, excise officers fly over the area looking for dark-stained buildings which may be holding illegal spirits. Just as in your photo, the staining is very pronounced – particularly on old “leaky” tiled roofs.
    I shall have a small Cognac this evening and drink a toast to Baudoinia compniacensis….thank you for the excuse!!

  5. Harry Thomas

    Great post. The pictures of the fungi are wonderful, and story of the naming of the fungi very interesting. As an aside I got three reminders to BPOTD and thought perhaps someone might have started on the Spirits mentioned above. 🙂 If that is the case, tis the season. Enjoy! Merry Christmas. Happy Hanukkah. Or even to celebrate the Winter Solstice and that Winter has arrived.

  6. Bonnie

    So it seems at least some angels are very black indeed.
    BPOTD is an utter trove of fascinating knowledge, images, commentary, day after day after day. Endless thanks, Daniel, and everyone else.
    Skaal! Good health to one and all.

  7. Joyce, in Toronto

    Merry Christmas. 🙂

  8. Elizabeth Revell

    What a fascinating thing! And now, some of us can raise a glass to Christmas and the Summer Solstice! (Sorry all you Northerners).
    And what about Brian’s comment re excise officers? Thanks for that, too.
    For me, it’s now Christmas Eve, so I wish all of you a happy holiday from toorrow.

  9. elizabeth a airhart

    white lilacs in the snow
    white crystals upon the blooms
    i revel in the glittering night
    my feet have wings as i walk
    the starry night to sit upon
    the moon and fill my cup
    merry christmas and joyful wishes to one and all

  10. Chris U

    Fascinating post with wonderful pictures. I love this blog! Have a great Holiday Season.

  11. Shirley

    i have some black mold that came with an airconditioner water leak growing on my 16th floor apt floor. Who knows it could be a relative of Torula?
    Fungi are more secretive in comparison to bacteria, it seems

  12. elizabeth a airhart

    to daniel and company and the world of people who visit bot a aday
    have a MERRY NEW YEAR

  13. Joyce, in Toronto

    Happy New Year!

  14. Randa

    I saw this fascinating effect in Cognac this past October! How curious, to see the stunning historic stone buildings blackened by the ‘angels’ share’. (We were lucky enough to taste the ‘other 90%’ after touring one of the cognac distillieries.) Thanks for this great article! Really interesting to see the magnified mould shots.

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