[[File:Coolship1.jpg|thumbnail|right|Copper Coolship at a brewery in Prague]]
'''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.
==Homebrew Coolships==
[[File:Ky coolship 2.jpg|thumbnail|right|Miniature Coolship by Devin Bell]]
[[File:Small-pasta-beer-coolship.jpg|thumbnail|right|[http://beerbybart.com/2014/04/02/slow-learning-sour-beer-experiments/ Boil kettle coolship by Gail Ann Williams.] Cheese cloth was used to keep out debris, and a chair was carefully placed to keep out wild raccoons.]]
Many homebrewers will construct a miniature coolship, as seen by Devin Bell's picture. Devin has reported good results from using his miniature coolship <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/1110677075627172/?comment_id=1110818382279708&offset=0&total_comments=7&comment_tracking=%7B%22tn%22%3A%22R4%22%7D Conversation with Devil Bell on the results of using his coolship. 7/16/2015.]</ref>. The benefit of building one is that a ball valve can be installed near the bottom of the coolship, which will make transferring the wort easier. Another option that some people have reported trying is purchasing a large stainless steel pans from a restaurant supply store, as well as food grade plastic trays.
The third option is to Homebrewers may use your boil kettle. At the 2015 National Homebrewer's Conference coolships in San Diego, James Howat's presentation, ''Wild their home brewhouse as a way to cool and Spontaneous Fermentation at Home'', brought up the issue of [https://en.wikipedia.org/wiki/Surface-area-to-volume_ratio surface area to volume ratio] <ref name="Howat">[http://www.homebrewersassociation.org/how-inoculate beers to-brew/resources/conference-seminars/ ''Wild and Spontaneous Fermentation at Home''. Presentation by James Howat at 2015 NHC.]</ref>be spontaneously fermented. The ''surface area to volume ratio'' purpose of a hot liquid, directly affects the cooling rate of that liquid coolship for homebrewers is identical to commercial brewers. (it affects For more information on the cooling rate process of all objectsbrewing with a coolship, not just liquids) <ref>see [[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 PhysicsSpontaneous Fermentation]]. 29 (2008) 369–384.]</ref>. In other wordsHowever, the greater vessel selected as a coolship generally will be determined by the surface area available resources of a given volume the homebrewer and the effect of liquid, the faster it cools. For example, imagine 100 liters of hot liquid is in a very wide and flat container. It coolship 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-be driven by the surface-area-to-volume-ratio/ this article for another explanation of how surface area to volume ratio affects cooling]the wort within the coolship.
James Howat===Common Homebrew Coolships===Homebrew coolships range from repurposed vessels to custom designed equipment. There are costs and benefits associated with each design that should be considered. Some homebrewers prefer to purchase or repurpose from the home suitable shallow, food grade containers used in cooking or catering. These include stainless steel or aluminum baking pans, large glass baking pans, food grade plastic trays and storage containers. These vessels are often cheap and may already be available in the home. It can be tough working with large vessels with no valve to drain the coolship into a fermentor. One must make sure the selected vessel is designed for use with hot liquids so it does not crack or melt. Cooling boiling wort in plastic containers that are not rated for boiling temperatures may leech chemicals from the plastic depending on what they contain, even if they are food grade. Others design coolships using specialized equipment fabricated for that purpose or created out of stainless steel or copper parts. An easy route to design a coolship may employ restaurant supplies such as steel storage racks and stainless steel tubs. These designs allow for convenient features such as a ball valve for draining the cooled wort or screening to keep out break material from the boil kettle. The coolship can be built to an optimum surface area to volume ratio. These coolships are often the most expensive route but the most customized and durable. A third option is to use the boil kettle as a coolship. In this method the kettle is simply left outside after the boil. Here there is no need to purchase or design a separate vessel and it may already provide a valve to drain the cooled wort and handles for easy movement. However, by using the boil kettle the brewer has no choice in the surface area to volume ratio of the cooling wort and there is no opportunity to remove the break material from the wort prior to cooling. Regardless of the method selected, the surface area to volume ratio should be carefully considered due to its affects on cooling and microorganism populations in the spontaneous fermentation. ===Surface Area to Volume Ratio===Abbreviated '''SA:V''', the surface area to volume ratio is the proportion between the surface area of the wort (the dimensions of the wort exposed to the sides of the vessel), and the volume of the wort. The SA:V affects the cooling rate of the wort. In addition to this, the surface area of the top of the vessel which is exposed to air in proportion to the volume of wort potentially affects the inoculation rate of the vessel. ====Cooling Rate====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''s . 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 find 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>. Some brewers claim that controlling the speed of cooling is important to assembling a desired blend of microorganisms in the wort <ref name="Howat"></ref>. Microbes survive and multiply at different temperatures and cooling too long or too fast may produce a beer that lacks desirable character or possesses an excess of undesirable character. A larger surface area of wort will allow for greater inoculation of microbes although if the wort cools too quickly the majority of inoculation will occur at cooler temperatures and affect the ratio and growth of various microbes in the wort. (For more information on the effects of the cooling rate see [[Spontaneous Fermentation]].) Scaling a commercial-sized coolship down to homebrewing volumes will produce a coolship that does not match the surface area to volume ratio of the larger coolship. For this reason, the surface area to volume ratio should be the driving factor in determining how to design the shape and depth of a homebrewing coolship. In his 2015 National Homebrewer's Conference presentation, Wild and Spontaneous Fermentation at Home, James Howat provides a comparison of the surface area to volume ratios between a 36 BBL coolship and a 10 gallon coolship scaled down linearly from the 36 BBL coolship:<ref name="Howat"></ref>.
<code>
:Example of a 36 bbl coolship:
::Dimensions of the example 36 coolship: 10 ft ' x 10 ft ' x 1.5 ft'.
::Wort volume = 1122 gallons = 150 cubic feet.
::Surface area of the top surface of the wort (2wl + 2lh + 2wh) = 100 square feet260 sq. ft.::Surface Area to Volume ratio = 100260/150 = '''01.6773''' square feet sq. ft. per cubic foot.
:Example of a 10 gallon coolship:
::Dimensions of the example "mini-10 gallon coolship": 2.5 ft ' x 2.5 ft ' x 0.20 ft (2.4 inches).'
::Wort volume: 9.35 gallons = 1.25 cubic feet.
::Surface area of the top surface of the wort (2wl + 2lh + 2wh) = 614.5 sq.25 square feetft.::Surface Area to Volume ratio = 614.255/1.25 = '''511.6''' square feet sq. ft. per cubic foot <ref name="Howat"></ref>.
</code>
The above This example shows that the surface area to volume indicates a substantially lower ratio of for the 36 bbl BBL coolship is much less than . At the surface area to volume lower ratio of , the 10 gallon coolship, thus it wort will cool considerably slower. A typical boil kettle (math As a result difference in cooling rate between the two coolships, the inoculation rate and ratio between microorganisms will differ. Designing a coolship for homebrew volumes may result in a coolship that does not provided due appear similar to its larger companions. To get as close to it involving circles) has the 1.73 ratio of the 36 BBL coolship with our 10 gallon example, the dimensions that provide would have to be as close to a cube as possible with dimensions approximately 1.1' x 1.1'x 1.03'surface area . This still only gives a SA:V of 4.9 sq. ft. per cubic foot. A homebrewer desiring a more shallow vessel may insulate the coolship to slow the cooling rate although this may affect the inoculate rate. A typical homebrew-volume ratio'' that boil kettle is closer to the 36 bbl larger coolship (estimated 1-2 square feet sq. ft. per cubic foot). Further insulation of and insulating the boil kettle when using it as a coolship may help obtain a slow the cooling rate closer to that is comparable of a commercial-volume coolship. ====Inoculation Surface Area====The ''top'' surface area to volume ratio affects the inoculation rate. Some brewers may want their coolship inoculation rate to be somewhere near what commercial coolships are. An example to find the SA:V ratio of just the top surface using the same two coolship dimensions follows: <code>:Example of a 36 bbl coolship:::Dimensions of the 36 coolship: 10' x 10' x 1.5'.::Wort volume = 1122 gallons = 150 cubic feet. Other factors that influence ::Surface area of the cooling rate top surface of the wort are (w x l) = 100 sq. ft.::Surface Area to Volume ratio = 100/150 = '''0.67''' sq. ft. per cubic foot :Example of a 10 gallon coolship:::Dimensions of the 10 gallon coolship: 2.5' x 2.5' x 0.20'::Wort volume: 9.35 gallons = 1.25 cubic feet.::Surface area of the temperature between top surface of the wort and its surroundings(w x l) = 6.25 sq. ft.::Surface Area to Volume ratio = 6.25/1.25 = '''5''' sq. ft. per cubic foot</code> The example above shows that the shallow 10 gallon coolship also has a much larger ''top'' surface area to volume ratio. ====Coolship SA:V Calculator==== 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 what the select "Microsoft Excel (.xlsx)":* [https://endocs.wikipediagoogle.orgcom/spreadsheets/wikid/1HFBTCt99OQ9-jSGI9jBZXwC6SqtZZVwlpXYw2rjLO4k/Thermal_conductivity thermal conductivityedit#gid=90184859 Original spreadsheet by Mark B. Fry (download and save a copy to use).] is of the material that the coolship is made out of* [https://docs.google.com/spreadsheets/d/1gB4347cP70Sw6topMoOvDydMYQcS2PF7M0Yl0vgbZbk/edit#gid=1777054704 Updated version by Joe Idoni with tab for rectangular coolships (second tab; download and save a copy to use).]
Another factor that is affected by the surface area to volume ratio is the inoculation rate==Commercial Coolships=====Manufacturers===Any metal tank manufacturer can generally build a coolship <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/1327576813937196/?comment_id=1327588103936067&comment_tracking=%7B%22tn%22%3A%22R3%22%7D Conversation with Joe Wells on MTF. The larger the surface area, the more microbes that are collected06/11/2016.]</ref>. However, it has been shown below are manufacturers that the surface area to volume ratio of large commercial coolships is adequate for collecting microbes, so specialize in theory this shouldn't be a concern their construction for homebrewers <ref name="Howat"><commercial breweries: * [http://www.foedercrafters.com/koelschip/ref>Foedercrafters. For more information on the process of brewing with a coolship, see ]* [http://www.metalcraftfabrication.com/ Metal Crafters Fabrication.]* [Spontaneous Fermentationhttp://nsibrew.com Newlands (copper coolship).]].
Some commercial brewers have reported positive results from using industrial maple syrup boil pans. [https:''Editor//www.facebook.com/groups/MilkTheFunk/permalink/1459172714110938/?comment_id=1459763314051878&comment_tracking=%7B%22tn%22%3A%22R2%22%7D See this MTF thread] for more information.===Miscelaneous Information===* [https://www.facebook.com/groups/MilkTheFunk/permalink/1637570519604489/?comment_id=1637600782934796&reply_comment_id=1637627056265502&comment_tracking=%7B%22tn%22%3A%22R%22%7D James Howat's note: a discussion on the merits comparison of cooling rates for copper versus stainless steel coolships is worthy of a separate, in-depth analysis, and currently isn't covered hereon MTF (multiple subreplies).'']
==See Also==
===Additional Articles on MTF Wiki===
* [http://www.milkthefunk.com/ccc/ MTF Coolship Cooling Calculator]
* [[Spontaneous Fermentation]]
* [[Lambic]]
===External Resources===
* [https://docs.google.com/spreadsheets/d/1HFBTCt99OQ9-jSGI9jBZXwC6SqtZZVwlpXYw2rjLO4k/edit#gid=90184859 Coolship SA:V calculator with approximation of cooling rate by Mark B. Fry (download and save a copy to use).]
* [https://www.youtube.com/watch?v=L3sijnoW5HU King's Coolship, BrewingTV Episode 42].
* [http://lambicandwildale.com/tag/cool-ship/ Lambic and Wild Ale blog; ''Cool Ship'' posts.]
* [http://www.browneandbitter.com/2015/05/spontaneous-fermentation-ii-success.html Amos Browne's second attempt (Browne and Bitter blog) with lessons learned from the first attempt.]
* [http://beerbybart.com/2014/04/02/slow-learning-sour-beer-experiments/ ''Slow Learning: Sour Beer Experiments'', by Gail Ann Williams.]
* [http://www.blackprojectbeer.com/blog/ Black Project's Coolship explanation by James Howat.]
* [https://www.facebook.com/blackprojectbeer/videos/580667305468055/ Live interview with James Howat while filling his new coolship.]
* [https://translate.google.com/translate?sl=auto&tl=en&js=y&prev=_t&hl=en&ie=UTF-8&u=https%3A%2F%2Fbelgianbeergeek.be%2F2016%2F11%2F27%2Fcoolship-the-yeast-over-koelschepen-en-beestjes%2F&edit-text=&act=url "Cool Ship & The Yeast - About reefers and critters" by Belgian Beer Geek blog; tech specs on commercial Belgian lambic coolships.]
==References==