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Many homebrewers will construct Homebrewers may use coolships in their home brewhouse as a miniature coolship, as seen by Devin Bell's pictureway to cool and inoculate beers to be spontaneously fermented. Devin has reported good results from using his miniature The purpose of a coolship <ref>[https://www.facebookfor homebrewers is identical to commercial brewers.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 (For more information on the results process of using his brewing with a coolship. 7/16/2015., see [[Spontaneous Fermentation]]</ref>. ) The benefit of building one is that However, the vessel selected as a ball valve can coolship generally will be installed near determined by the available resources of the bottom homebrewer and the effect of the coolship, which will make transferring be driven by the surface to volume ratio of the wort easierwithin the coolship. 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 use your boil kettle. At the 2015 National Homebrewer's Conference in San Diego, 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-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 affects the 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 in thermal physics: ==Common Homebrew Coolships===Homebrew coolships range from cheese cube physics repurposed vessels to animal metabolismcustom designed equipment. Gorazd Planinsic There are costs 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]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. 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 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 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 Example===James HowatThe 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, 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 example of how . BBC website, Bitesize section. Retrieved 7/24/2015.]</ref>. The most important factor is the ambient temperature, but the easiest variable to find control is the surface area to volume ratio . The greater the surface area of a coolship is found belowgiven 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. Note that this 29 (2008) 369–384.]</ref>. For example , imagine 100 liters of hot liquid is not 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 true spherical container. See [http://wordpress.mrreid.org/2011/10/20/spherical-ice-cubes-and-surface -area -to -volume -ratio equation, but a simplified version / this article for another explanation of how surface area to volume ratio affects cooling]. Some brewers claim that only measures controlling the top surface speed of cooling is important to assembling a desired blend of microorganisms in the coolshipwort <ref name="Howat">[http://www.homebrewersassociation.org/how-to-brew/resources/conference-seminars/ ''Wild and Spontaneous Fermentation at Home''. It makes sense to only consider Presentation by James Howat at 2015 NHC.]</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 top surface ratio and growth of various microbes in the coolship since most 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>. AdditionallyTo keep the comparison simple, this example shows that it compares only on the surface area of wort exposed to volume ratio the air because this is not linear across vessel sizeswhere the most heat escapes from the wort. (A comparison including the total surface area of wort would show an even larger difference between the examples.)

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

::Surface area of the top surface of the wort = 100 square feetsq. ft.::Surface Area to Volume ratio = 100/150 = '''0.67''' square feet sq. ft. per cubic foot.

::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 = 6.25 square feetsq. ft.::Surface Area to Volume ratio = 6.25/1.25 = '''5''' square feet sq. ft. per cubic foot.

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 not provided due to it involving circles) has dimensions that provide a surface area to volume ratio that is closer to the 36 bbl coolship (estimated 1-2 square feet per cubic foot). Further insulation of the boil kettle may help obtain As a result difference in cooling rate that is comparable to the 36 bbl coolship. Other factors that influence the cooling rate of wort are the temperature between the wort and its surroundingstwo coolships, and the [https://en.wikipedia.org/wiki/Thermal_conductivity thermal conductivity] of the material that the coolship is made out of. Another factor that is affected by the surface area to volume ratio is the inoculation rate. The larger the surface area, the more microbes that are collected. However, it has been shown that the surface area to volume and ratio of large commercial coolships is adequate for collecting microbes, so in theory this shouldn't be a concern for homebrewers that are using a boil kettle since the surface area to volume ratio of a boil kettle is still more than a large commercial coolship <ref name="Howat"></ref>. For more information on the process of brewing with a coolship, see [[Spontaneous Fermentation]]between microorganisms will differ.

:Designing a coolship for homebrew volumes may result in a coolship that does not appear similar to its larger companions. To match the 0.67 ratio of the 36 BBL coolship with our 10 gallon example, the dimensions would have to be approximately 0.915'x 0.915'Editorx 1.49' with a surface area of 0.8375's note: . A homebrewer desiring a discussion on more shallow vessel may insulate the coolship to slow the merits of cooling rates for coolships rate although this may affect the inoculate rate. A typical homebrew-volume boil kettle is worthy closer to the larger coolship (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 that of a separate, incommercial-depth analysis, and currently isn't covered herevolume coolship.''