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'''Coolship''' (the 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 large surface area in relation to mass ratio volume allows for more relatively efficient cooling. Contemporary usage includes any open fermentor used It is also an integral step in the production process of beer, even when using modern mechanical cooling techniquesmaking Belgian lambic and other [[Spontaneous_Fermentation|spontaneously fermented beers]]. TraditionallyHistorically, ''coolships'' were constructed of wood, but later were lined with iron or copper for better thermal conductivity. Most modern constructed coolships are made from stainless steel, although copper coolships are still used in many Belgian lambic breweries as well as a few breweries outside of Belgium. Pre-dating the specific application of coolships by Belgian lambic brewers for inoculation during cooling, some German and English brewers also still use copper coolships (''kühlschiff'' in German and "cooler" in Great Britain) as chillers to partially cool wort to 55-75°C (131-167°F) before either chilling the wort in a closed system or transferring the warm wort to a fermenter to cool and finally pitch yeast, a process which was once common throughout Europe <ref>[http://craftybeergirls.com/2018/03/18/coolship-field-trip/ Lauren Lerch. "Coolship Field Trip". Crafty Beer Girls blog. Retrieved 03/18/2018.]</ref><ref>[http://www.uerige.de/brauerei-brauprozess.html "Malz – aus Gerste und Weizen ". Zum Uerige website. Retrieved 03/18/2018.]</ref><ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/2814130411948488/ Various members of MTF. Milk The Funk thread on the use of coolships in historical German brewing. 07/28/2019.]</ref><ref>[http://zythophile.co.uk/2019/10/18/do-you-gyle-your-ale-after-it-leaves-the-cooler-and-finishes-fermenting-in-the-vat-or-krausen-your-beer-post-coolship-when-its-run-out-of-the-foeder Martyn Cornell. Zythophile website. 10/18/2019. retrieved 10/18/2019.]</ref>. Saison breweries used coolships during the 1800's in a similar fashion to German brewers to cool the wort before pitching yeast <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/2275507945810740/?comment_tracking=%7B%22tn%22%3A%22R%2317%22%7D Georges Lacambre. Dec, 1851. Translated by Lucas Blasty on Milk The Funk Facebook group.]</ref>.  Contemporary usage also includes using a coolship as an open fermentor for the production of non-sour beer. For example, [https://web.archive.org/web/20220126000613/https://www.anchorbrewing.com/blog/brewing-insights-open-fermentation/ Anchor Brewing Co] fermented beer openly, but because the wort is pre-chilled before entering the vessel, Anchor Brewing no longer refers to these as "coolships" but as "open fermenters" <ref>[https://web.archive.org/web/20230326181248/https://www.anchorbrewing.com/blog/anchor-terminology-coolship/ "Anchor Terminology: Coolship". Anchor Steam website. 04/12/2012. Retrieved 09/10/2018.]</ref>. Contemporary experimental usage of coolships includes allowing wort to cool and become inoculated with microbes from the environment, as well as adding cultured yeast at some point in the process, and optionally using the coolship as an open fermenter to conduct the primary fermentation in rather than conducting the primary fermenation in barrels like in Belgian lambic brewing. This is not considered to be full "spontaneous fermentation" since yeast and/or lactic acid bacteria are added to produce a more controlled fermentation, but the resulting beer might benefit from or be otherwise altered by the wild microbes or the effects of the lack of head pressure/exposure to oxygen caused by cooling (and optionally fermenting) the wort in a coolship <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/2987548407940020/ Brandon Jones of Yazoo Brewing Co. Milk The Funk Facebook group thread on using a coolship and pitching Bootleg Biology yeast. 10/18/2019.]</ref>. A less common practice that has been gaining some traction in the US is using a portable coolship. These coolships are designed to be transported, often in the back of pickup trucks. The coolship should have a baffle that prevents the dangerously hot wort from spilling out of the coolship. The coolship can then be transported anywhere to inoculate the wort. See [http://allaboutbeer.com/article/portable-coolships/ this All About Beer Magazine article]. This article will focus on the use of a coolship to initiate spontaneous fermentation and will not significantly address the use of coolships to partially cool wort as in the German/English/saison methods of chilling wort or to conduct open fermentation.  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.

Homebrewers may use coolships in their home brewhouse as a way to cool and inoculate beers to be spontaneously fermented. The purpose of a coolship for homebrewers is identical to commercial brewers. (This section For more information on the process of brewing with a coolship, see [[Spontaneous Fermentation]].) However, the vessel selected as a coolship generally will be determined by the available resources of the homebrewer and the effect of the coolship will be driven by the surface area to volume ratio of the wort within the coolship. ===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 progresscooking 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.)

Many homebrewers will construct A third option is to use the boil kettle as 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 In this method the kettle is simply left outside after the results of using his coolshipboil. 7/16/2015.]</ref>. The benefit of building one Here there is that no need to purchase or design a separate vessel and it may already provide a ball valve can be installed near to drain the cooled wort and handles for easy movement. However, by using the bottom boil kettle the brewer has no choice in the surface area to volume ratio of the coolship, which will make transferring the cooling wort easier. Another option that some people have reported trying and there is purchasing a large stainless steel pans no opportunity to remove the break material from a restaurant supply store, as well as food grade plastic traysthe wort prior to cooling.

The third option is to use your boil kettle. At Regardless of the 2015 National Homebrewer's Conference in San Diegomethod selected, James Howat's presentation, ''Wild 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-should be carefully considered due to-brew/resources/conference-seminars/ ''Wild and Spontaneous Fermentation at Home''. Presentation by James Howat at 2015 NHC.]</ref>. The ''surface area to volume ratio'' of a hot liquid, directly its affects the on cooling rate of that liquid (it affects the cooling rate of all objects, not just liquids) <ref>[http://www.fmf.uni-lj.si/~planinsic/articles/Cheese%20cubes_EJP.pdf The surface-to-volume ratio and microorganism populations in thermal physics: from cheese cube physics to animal metabolism. Gorazd Planinsic and Michael Vollmer. European Journal of Physics. 29 (2008) 369–384.]</ref>. In other words, the greater the surface area of a given volume of liquid, the faster it cools. 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]spontaneous fermentation.

===Surface Area to Volume Ratio Example===James HowatAbbreviated '''SA:V'''s example , 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 how the wort. In addition to find this, the surface area of the top of the vessel which is exposed to air in proportion to the volume ratio of wort potentially affects the inoculation rate of the vessel, although this aspect has not been studied that we are aware of.  ====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 found belowa 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. Note that this example is not a true ~1:22:00 minutes in.]</ref>), and the surface area to volume ratio equation<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 simplified version that only measures given liquid the top 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 coolshipfor the given volume of wort <ref name="Howat">[http://www.homebrewersassociation.org/how-to-brew/resources/conference-seminars/ ''Wild and Spontaneous Fermentation at Home''. It makes sense Presentation by James Howat at 2015 NHC.]</ref>.  Some brewers claim that controlling the speed of cooling is important to only consider assembling a desired blend of microorganisms in the top 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 coolship since most ratio and growth of various microbes in the wort. (For more information on the effects of the heat cooling rate see [[Spontaneous Fermentation]].) Scaling a commercial-sized coolship down to homebrewing volumes will escape from produce a coolship that does not match the uncovered top surface area to volume ratio of the larger coolship. A true For this reason, the surface area to volume ratio would show an even larger difference 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 two example coolships below 36 BBL coolship <ref name="Howat"></ref>. Additionally, this example shows that the surface area to volume ratio is not linear across vessel sizes.

::Dimensions of the example 36 coolship: 10 ft ' x 10 ft ' x 1.5 ft'.

::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(56. 8 cm² per L)

::Dimensions of the example miniature 10 gallon coolship: 2.5 ft ' x 2.5 ft ' x 0.20 ft (2.4 inches).'

::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(380.6 cm² per L)

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 lower ratio, the wort will cool considerably slower. As a result difference in cooling rate between the two coolships, the surface area inoculation rate and ratio between microorganisms may differ. Designing a coolship for homebrew volumes may result in a coolship that does not appear similar to its larger companions. To get as close to volume the 1.73 ratio of the 36 BBL coolship with our 10 gallon coolshipexample, thus it will cool slowerthe dimensions would have to be as close to a cube as possible with dimensions approximately 1.1' x 1.1' x 1.03'. 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 boil kettle is closer to the larger coolship (math not provided due estimated 1-2 sq. ft. per cubic foot) and insulating the kettle when using it as a coolship may slow the cooling rate closer to it involving circles) has dimensions that provide of a commercial-volume coolship. ====Inoculation Surface Area====The ''top'' surface area to volume ratio that is closer 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. ::Surface area of the top surface of the wort (w x l) = 100 sq. ft.::Surface Area to Volume ratio = 100/150 = '''0.67''' sq. ft. per cubic foot (estimated 22.0 cm² per L)  :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 = 1-2 square .25 cubic feet .::Surface area of the top surface of the wort (w x l) = 6.25 sq. ft.::Surface Area to Volume ratio = 6.25/1.25 = '''5''' sq. ft. per cubic foot(164 cm² per L)</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). Further insulation In order to use the files they must be downloaded. Click "File", "Download as", and select "Microsoft Excel (.xlsx)":* [https://docs.google.com/spreadsheets/d/1HFBTCt99OQ9-jSGI9jBZXwC6SqtZZVwlpXYw2rjLO4k/edit#gid=90184859 Original spreadsheet by Mark B. Fry (download and save a copy to use).]* [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).]* [https://www.facebook.com/groups/MilkTheFunk/permalink/2440331772661689/ Coolship calculator by Mark Hamon that includes evaporative cooling rates.] ====Testing Cooling Rates==== These resources have tested the cooling rates of various coolship types. * [http://www.archaicpursuit.com/2018/03/2015-coolship-experiment-cooling-rate.html?m=1 Caleb Buck's 2+ year experiment testing the boil difference between cooling rates by cooling in an insulated cooler and a similarly sized aluminum kettle may help obtain without insulation]. See also the associated [https://www.facebook.com/groups/MilkTheFunk/permalink/1183899281638284/?hc_location=ufi MTF thread].* [http://thirdleapbrew.com/technical/the-great-homebrew-coolship-experiment/ Andrew Kazanovicz plotted the cooling rates of a Bayou Classic 1082 82 qt kettle versus an Igloo 10 gallon insulated cooler.] See also the associated [https://www.facebook.com/groups/MilkTheFunk/permalink/1932089090152629/ MTF thread].* [http://homebrewingfun.blogspot.com/2018/04/update-and-blend-of-spontaneous-beers.html Adam Kielich measures the cooling rate over time of small batches, and reports the results.] See also the associated [https://www.facebook.com/groups/MilkTheFunk/permalink/2094624910565712/ MTF thread].* [https://www.facebook.com/groups/MilkTheFunk/permalink/3137607142934145/?comment_id=3137680236260169 Andrew Zinn's cooling rate data for a 45bbl coolship, 30 bbl brewhouse.] ==Commercial Coolships== This table shows the dimensions of various commercial coolships (sources noted below the table). The volume of the coolships has been calculated from the dimensions, and therefore it is slightly larger than the practical filling volume. Surface area:volume is calculated for the top surface exposed to air for both the maximum fill and the approximate batch sizes as well as the total surface area (including the walls and bottom of the coolship). Some breweries use multiple coolships at once. When multiple identical coolships are used, numbers in parentheses following brewery names indicate the number of coolships used and the volume given is the total combined volume of these coolships. Metric is used so that the calculations are easier. For brewers who prefer ft²:ft³, 10 cm²:L is equal to 0.305 ft²:ft³.  {| class="wikitable sortable"|-! Brewery !! Coolship Material !! Volume (total if multiple) (HL)!! Surface Area:Volume (top, min) (cm²:L)!! Actual Surface Area:Volume (top, estimated) (cm²:L)!! Surface Area:Volume (Total, min) (cm²:L)!! Brew Size (HL, approx)!! Length (cm)!! Width (cm)!! Height (cm)|-| 3 Fonteinen (4) || Stainless Steel || 62.3 || 35.7 || 55.6 || 90.8 || 40 || 400 || 139 || 28|- | Cantillon<nowiki>*</nowiki> || Copper || 75 || 33.3 || 38.5 || 74.7 || || 500 || 500 || 30|-| De Troch (2) || Stainless Steel || 57.3 || 38.3 || 68.7 || 88.7 || 32 || 349.3 || 314.5 || 26.1|-| Lindemans (new) || Stainless Steel || 234.3 || 19.9 || 23.3 || 46.4 || 200 || 1113.3 || 419.3 || 50.2|-| Timmermans || Copper || 236.1 || 26.8 || 57.5 || 58.6 || 110 || 810.1 || 781.3 || 37.3|-| Omer Vander Ghinste || Copper || 198 || 18.2 || 25.7 || 43.0 || 140 || 600 || 600 || 55|-| Van Honsebrouck || Stainless Steel || 352.5 || 17.2 || 26.4 || 39.6 || 230 || 778.9 || 778.9 || 58.1|-| Liefmans (2)<nowiki>**</nowiki> || Copper || 542 || 28.2 || 31.9 || 62.2 || 480 || 1749 || 440 || 35.4|-| Black Project (full)<nowiki>***</nowiki> (Closed) || Copper || 13.6 || 21.9 || 24.8 || 68.4 || 12 || 243.8 || 121.9 || 45.7|-| Black Project (half) (Closed) || Copper || 6.8 || 21.9 || 24.8 || 76.6 || 6 || 121.9 || 121.9 || 45.7|-| Jester King || Copper || 84.9 || 21.9 || 50.2 || 53.6 || 37 || 609.6 || 304.8 || 45.7|-| Mantra (Closed) || Stainless Steel || 18.9 || 32.8 || 35.2 || 83.1 || 17.6 || 381 || 162.6 || 30.5|-| Monkish || Stainless Steel || 22.6 || 16.4 || 23.2 || 54.2 || 16 || 243.8 || 121.9 || 91.4|-| Orpheus || Stainless Steel || 28.3 || NA || ~26 || 76.7 (actual) || 10 || 91 (radius) || NA || 43.2 (fill height)|-| The Referend (full)<nowiki>****</nowiki>|| Stainless Steel || 55.4 || 21.9 || 34.5 || 56.1 || 35.2 || 508.0 || 238.8 || 45.7|-| The Referend (small) || Stainless Steel || 19.4 || 21.9 || 36.3 || 63.4 || 11.7 || 177.8 || 238.8 || 45.7|-| The Referend (large) || Stainless Steel || 36.0 || 21.9 || 33.6 || 58.2 || 23.5 || 330.2 || 238.8 || 45.7|-| Sour Cellars || Stainless Steel || 7.4 || 17.5 || 18.0 || 70.7 || 7.2 || 135.9 || 95.3 || 57.2|-| Strange Roots Experimental Ales || Stainless Steel || ? || ? || ? ||? || ? || ? ||? || ?|-| Trinity ||Stainless Steel || 27.2 || 10.9 || 17.5 || 46.5 || 17 || 243.8 || 121.9 || 91.4|-| The Veil || Stainless Steel || 31.7 || 16.4 || 29.5 || 50.4 || 17.6 || 243.9 || 213.3 || 60.9|-| Yazoo<nowiki>*****</nowiki> || Stainless Steel || 25.7 || 14.1 || 21.3 || 49.2 || 23.5 || 198 || 183 || 71|-| Little Wolf<nowiki>******</nowiki> || Stainless Steel || 16.1 || 22.2 || 27 || 79.6 || 12 || 650 || 55 || 45|-| Shady Oak Barrel House<nowiki>*******</nowiki> || Stainless Steel || 5.98 || 30.3 || 34.2 || 94.6 || 5.3 || 183 || 99 || 33|-| Atom Brewing Company<nowiki>********</nowiki> || Copper || 5.678 || 25.4 || 28.26 || 84.1 || 5.1 || 119.4 || 120.7 || 39.4|-|}<nowiki>*</nowiki>An extra vessel is available to hold additional wort in case the wort volume exceeds the coolship capacity <nowiki>**</nowiki>These coolships were used to cool wort to an intermediate temperature (~50-60 C) before finishing cooling with a Baudelot chiller, rather than for inoculation. They are no longer in use. <nowiki>***</nowiki>The Black Project coolship is a single vessel with a divider allowing the coolship to be half filled with the depth and exposed surface area remaining the same as if it were completely filled. <nowiki>****</nowiki>The coolship at The Referend Bier Blendery is a single vessel divided into two unequal compartments. This allows the coolship to be filled with three different brew sizes while maintaining the same fill depth and exposed surface area. <nowiki>*****</nowiki>The coolship at Yazoo is comparable custom designed to be used year round and double as an open fermenter. Fabrication by Badger Fabrication in Wisconsin. <nowiki>******</nowiki>The Little Wolf coolship is not designed to be a coolship, but rather a vessel designed for soaking all of the 36 bbl hoses used in the brewery, thus the less traditional dimensions <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/2321660844528783/?comment_id=2322247021136832&reply_comment_id=2322641964430671&comment_tracking=%7B%22tn%22%3A%22R0%22%7D Stefan Wiswedel. milk The Funk Facebook group thread on Little Wolf's "coolship". 10/15/2018.]</ref>. <nowiki>*******</nowiki>Shady Oak Barrel House coolship has a top that can be clamped down with a pressure release valve for transferring hot wort within the coolship to another location <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/2371134149581452/?comment_id=2371475189547348&reply_comment_id=2371486176212916&comment_tracking=%7B%22tn%22%3A%22R5%22%7D Dustin Carver. Milk The Funk Facebook group thread about Shady Oak Barrel House coolshiplid, clamps, and PRV. 11/16/2018.]</ref>. <nowiki>********</nowiki>Atom Brewing Company's coolship slopes to 15.5 inches; calculations do not include this slope. This table is based on data collected by [https://belgianbeergeek.be/2016/11/27/coolship-the-yeast-over-koelschepen-en-beestjes/ Belgian Beer Geek] on the characteristics of coolships in various breweries and from MTF member contributions<ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/1790239601004246/ MTF thread about coolship dimensions]</ref>. ===Overhangs and Other factors Innovations===Some breweries have opted to craft overhangs that influence simulate a wooden ceiling above their coolship. The idea is to simulate some [[Lambic|lambic]] breweries that have relatively low ceilings made from wood. During the cooling rate of the wort in the coolship, vapor rises to the ceiling, condenses, and then drips back down into the coolship, potentially carrying microbes that are living on the wood of the temperature between ceiling (see also [[Spontaneous_Fermentation#Notes_on_the_Source_of_Microbes|Sources of Microbes in Spontaneous Fermentation]]). Other examples of innovative customizations to the coolship design include Yazoo's Embrace The Funk Coolship wort and its surroundingsimmersion chiller for experimenting with cooling at warmer ambient temperatures, and Black Project's coolship that can be split into half batches. <gallery mode=packged>File:Antidoot Coolship.jpg|[https://www.facebook.com/groups/MilkTheFunk/permalink/1999185740109630/ Overhang above the coolship at Antidoot - Wilde Fermenten. Image provided by Tom Antidoot Jacobs.] File:Yazoo Coolship.jpg|[https://embracethefunk.com/2017/03/02/big-coolship-batch-1/ Wort chiller for Yazoo's Embrance The Funk coolship. Image provided by Brandon Jones.]File:Black Project coolship.jpg|[http://www.blackprojectbeer.com/report/we-refuse-to-compromise Divider for "half batches" at Black Project Spontaneous Ales. Image provided by Scott Davidson.]</gallery> ===Manufacturers===Any metal tank manufacturer can generally build a coolship, so local resources are likely to be available <ref>[https://enwww.wikipediafacebook.orgcom/wikigroups/Thermal_conductivity thermal conductivityMilkTheFunk/permalink/1327576813937196/?comment_id=1327588103936067&comment_tracking=%7B%22tn%22%3A%22R3%22%7D Conversation with Joe Wells on MTF. 06/11/2016.] of the material </ref>. However, below are manufacturers that the specialize in their construction for commercial breweries: * [https://www.foedercrafters.com/koelship Foedercrafters.]* [http://www.metalcraftfabrication.com/ Metal Crafters Fabrication.]* [http://nsibrew.com Newlands (copper coolship is made out of).]* [https://www.glaciertanks.com/koelschips.html Glacier's advanced design koelchip.]* [https://www.facebook.com/Anderson-Brewing-Consulation-LLC-364074707362014 Anderson Brewing Consultation (via MTF'er Chris Anderson).]* [https://www.facebook.com/groups/MilkTheFunk/permalink/3943319839029534/ MTF thread]. Some commercial brewers have reported positive results from using industrial maple syrup boil pans. [https://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.

Another factor that is affected ===Miscellaneous Information===* [https://www.youtube.com/watch?v=scg7xird4RU Coolships vs open fermentaters vs spontaneous fermentation presentation by the surface area to volume ratio is the inoculation rateRon Smith and John Allison (Foam Blowers Homebrew Club).]* [https://www. The larger the surface area, the more microbes that are collectedfacebook. However, it has been shown that the surface area to volume ratio com/groups/MilkTheFunk/permalink/1637570519604489/?comment_id=1637600782934796&reply_comment_id=1637627056265502&comment_tracking=%7B%22tn%22%3A%22R%22%7D James Howat's comparison of large commercial copper versus stainless steel coolships is adequate for collecting microbes, so in theory this shouldn't be on MTF (multiple subreplies).]* [https://www.facebook.com/groups/MilkTheFunk/permalink/1897849993576539/ 150 gallon mobile coolship from Crooked Run Brewing.]* [https://www.facebook.com/groups/MilkTheFunk/permalink/2375730269121840/ Mikkeller Baghaven mobile coolship with a concern for homebrewers that are using hard-piped centrifuge pump connected to a boil kettle since tank under the surface area to volume ratio is still more than a large commercial coolship <ref namefor easier transfer.]* [https://www.facebook.com/groups/MilkTheFunk/permalink/2281960581832143/?comment_id="Howat"><2286467758048092&comment_tracking=%7B%22tn%22%3A%22R%22%7D Kyle Kohlmorgen's wooden wine barrel coolships.]* [https://ref>www.facebook. For more information on the com/groups/MilkTheFunk/permalink/1181778045183741/ Michael Detar's process of brewing with running wort through a tree trunk and into a wooden oak barrel to use as a coolship, see [[Spontaneous Fermentationcooling process.]].

:''Editor's note: ==Open Fermentation==Some commercial brewers have used their coolship to double as a discussion on the merits of cooling rates fermenter for coolships is worthy of a separateopen fermentation (not to be confused with [[Spontaneous Fermentation]]). For example, in-depth analysissee this [https://www.facebook.com/groups/MilkTheFunk/permalink/2196381667056702/ MTF thread]. For more information on open fermentation, see [https://www.youtube.com/watch?v=X9xT8DHOZFE Michael Dawson on BrewingTV] and currently isn't covered here[https://beerandbrewing.com/dictionary/xY1cRpZ5mD/open-fermentation/ this Beer & Brewing Magazine article].''

* [https://web.archive.org/web/20150509102029/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.]