Changes

'''Coolship''' (Anglicized version of the Dutch/Flemish ''koelschip'') is a type of fermentation vessel used in the production of beer. Traditionally, a ''coolship'' is a broad, open-top, flat vessel in which wort cools. The high surface to mass ratio allows for more efficient cooling. Contemporary usage includes any open fermentor used in the production of beer, even when using modern mechanical cooling techniques. Traditionally, ''coolships'' were constructed of wood, but later were lined with iron or copper for better thermal conductivity. See also the [http://www.milkthefunk.com/ccc/ MTF Coolship Cooling Calculator]. See [[Spontaneous_Fermentation#Cooling|Spontaneous Fermentation]] for information on dissolved oxygen in wort that is cooled overnight in a coolship.

The cooling rate of the exposed wort is influenced by a number of factors including the ambient temperature, the [https://en.wikipedia.org/wiki/Thermal_conductivity thermal conductivity] of the coolship material(for example, Jester King Brewery noted a faster, more preferable cooling rate for a 30 bbl coolship made from copper versus stainless steel because copper is a better thermal conductor <ref>[http://www.thebrewingnetwork.com/session-jester-king-brewery/ "Jester King Brewery"; Interview with Averie Swanson from Jester King Brewery. Brewing Network Session Podcast. 01/30/2017. ~1:22:00 minutes in.]</ref>), and the surface area to volume ratio <ref>[http://www.bbc.co.uk/schools/gcsebitesize/science/aqa/heatingandcooling/heatingrev6.shtml ''Energy transfer by heating''. BBC website, Bitesize section. Retrieved 7/24/2015.]</ref>. The most important factor is the ambient temperature, but the easiest variable to control is the surface area to volume ratio. The greater the surface area of a given liquid the faster it will cool <ref>[http://www.fmf.uni-lj.si/~planinsic/articles/Cheese%20cubes_EJP.pdf The surface-to-volume ratio in thermal physics: from cheese cube physics to animal metabolism. Gorazd Planinsic and Michael Vollmer. European Journal of Physics. 29 (2008) 369–384.]</ref>. For example, imagine 100 liters of hot liquid is in a very wide and flat container. It will cool much faster than if it was in a perfectly square container, and even faster still than if it was in a spherical container. See [http://wordpress.mrreid.org/2011/10/20/spherical-ice-cubes-and-surface-area-to-volume-ratio/ this article for another explanation of how surface area to volume ratio affects cooling].The more surface area to volume ratio, the more microorganisms that will be collected in the coolship for the given volume of wort <ref name="Howat">[http://www.homebrewersassociation.org/how-to-brew/resources/conference-seminars/ ''Wild and Spontaneous Fermentation at Home''. Presentation by James Howat at 2015 NHC.]</ref>.

Mark B. Fry's coolship SA:V calculator will calculate the SA:V for cylindrical kettles (updated by Joe Idoni to include a second tab for rectangular coolships). In order to use the files they must be downloaded. Click "File", "Download as", and select "Microsoft Excel (.xlsx)":