Two dual function stainless steel adaptors are connected to the top inlet and bottom outlet. The top adaptor allows for venting and also has a thermowell into which the temperature sensor is placed. The bottom adaptor is a so called pipe-in-pipe connection, one pipe is used to withdraw yeast while the outer pipe goes further up the cone to allow for beer removal. The SURF system allows for all standard fermentation operations including dry hopping.
The SURF’s fermentation/conditioning flexible liner is manufactured from food grade hydrocarbons which in combination with a fixed frame and specialised adaptors holds the fermenting beer in the same way as a unitank. However, this flexible liner is used just once, when the fermentation/condition process is complete the beer is transferred for carbonation & filling or to a bright beer serving tank and the liner is sent for recycling. In effect the SURF is a liner which sits inside a rigid container which provides structural integrity and cooling functionality.
The SURF Liner is supplied as a flat packed clean container and therefore does not require sanitation prior to use. Specially engineered steel adaptors are connected to the SURF liner nozzles prior to filling with cooled wort and yeast. Good sanitary practice is required when making and breaking connections to the SURF, these connections are termed “briefly exposed”. The SURF is held in place by means of a rigid container called a SURF “Shell”, the shape of which depends on the SURF model.
The standard SURF is cylindroconical and is held in a SURF Shell which is similar to a unitank. The SURF Shell is fitted with a cooling coil on the main cylinder.
It should be noted that the use of food grade plastic containers for the storage of finished beer is not new as this is quite common in mainland Europe. However, these so called “beer liners” are used for storage of finished beer and are very simple constructs with a single inlet/outlet. The beer liners are stored in a pressurised cigar shaped vessel which is orientated horizontally. Beer liners have become popular for establishments which carry large volumes of a single beer and they also eliminate the need to chemically clean and sanitise steel vessels.
The primary structural difference between the stainless steel unitank and the SURF Shell is that the latter is not a pressure rated vessel. The SURF shell is an open top container which is only used for holding the SURF Liner in place and providing cooling functionality. Unlike the unitank the SURF Liner only has two nozzles, one top and one bottom, two specialised steel adaptors allow for dual functionality on both nozzles. A so called pipe-in-pipe adaptor is fitted to the bottom nozzle to facilitate addition of wort/yeast and subsequent removal of beer through one pipe and removal of cold break and yeast via another pipe. The top adaptor comprises a closed end thermowell into which a temperature sensor is fitted and a vent tube for CO2 venting during anaerobic fermentation. Dry hopping is performed by simply removing the top adaptor and using a sanitised funnel to add hops, alternatively dry hopping can be achieved by circulating the beer around a tank or other container which holds the hops in place by means of a bag of steel filter. The beer is pumped from the SURF through the dry hop container and then returned to the SURF via the top nozzle which is normally used for venting. Dry hopping is normally performed once the off-gassing has finished to avoid loss of aroma due to CO2 stripping.
To facilitate ease of SURF Liner installation and removal the bottom element of the cone on the SURF shell is removable by means of adjustable toggle clamps.
As the beer does not contact the SURF shell there is no need for a high specification finish and sanitary design considerations. Additionally, a pressure relief valve is not required as the SURF is not pressure rated.
To absolutely minimise the cost of the SURF Shell the highly efficient insulation on the unit is not clad in steel. Steel cladding is useful when a rockwool type insulation is used which can shed particles and is easily damaged but for the robust insulation used on our SURF shells the expensive cladding has no benefit. Steel cladding does make the shiny vessels look good but the smooth finish black cladding on the SURF Shells is equally attractive and professional looking. The real beauty in any microbrewery is the brewhouse itself, mashtun and kettle which are sometimes clad in expensive copper to give that extra wow effect! In Microbreweries fermenters are often placed in cellars or a backroom so away with the steel cladding unless a brewer really wants it of course!
While the SURF Shell is a steel construction the simple design and reduced steel quantity means that the unit is significantly cheaper than a high specification sanitary design beer contacting unitank.