Carved natural-stone wine vessel
A wine fermentation and maturation tank carved from a single granite block, with a thick mineral shell and fitted metal closures and taps.
Equipment · Tanks and vats
Floating-lid tank
variable-capacity tank
A floating-lid tank is an open-top vessel whose separate lid rests at the liquid level. In contemporary stainless-steel models, an inflatable perimeter seal reduces the air space above a variable volume of wine, cider or juice.
A lid that follows the liquid
A floating-lid tank is a portable, open-top vessel designed for batches that do not always fill the same volume. Its circular lid rests on the liquid surface and can be lowered as the level falls. Many variable-capacity designs add an inflatable gasket around the lid, pressing it against the inner tank wall and limiting air exchange through the headspace. That lets a cellar keep a partly filled lot in one tank instead of moving it into a smaller fixed-volume vessel.
Speidel's FO1/FO2 line is a contemporary example. Its product specification describes an open top with a strengthening rim, a vaulted bottom, an external litre scale and three legs. The listed construction is AISI 304 stainless steel with a marbled exterior. This is a modern manufactured design, not a traditional vessel with a documented historical origin.
Sources for this section
Variable volume and the seal
When a tank is only partly full, the gap above the product can be much larger than it is at capacity. The floating lid follows the changing surface and reduces that headspace. The gasket is central to the arrangement: it must meet the tank wall evenly to separate the liquid surface from the open space above. Models that use an inflatable gasket may include a hand pump; the precise kit and fittings depend on the tank version.
Speidel describes the lid as keeping air out. That is the intended function of a correctly fitted seal, not a guarantee that oxidation cannot occur. The fermentation-vessels atlas notes that performance depends on the actual seal and how it is operated. A worn, poorly fitted or incorrectly inflated gasket can weaken the intended barrier. A tank's construction does not replace appropriate cellar hygiene or process controls.
Sources for this section
A contemporary wine and beverage tank
Speidel lists FO1/FO2 capacities from 220 to 910 litres and names storage, maturation and fermentation among the uses. The same page lists wine, juice, cider and industrial applications. The equipment is therefore not limited to wine, although the atlas entry places floating-lid tanks in contemporary small-winery and beverage work. Its open top and moving lid distinguish it from a fixed-head fermenter, a coopered barrel or a closed storage tank.
The manufacturer specifies outlet options separately for FO1 and FO2, and points buyers to product specification sheets for details. A Norwegian retailer's 300-litre FO1 listing gives a model-specific example: 139 cm high by 63 cm diameter, with a floating-lid kit and pump. Those measurements and accessories should not be generalized to the full 220–910-litre range or to other manufacturers.
Selecting and caring for a model
Select a tank by batch volume and intended use, then check the specific version's dimensions, lid assembly, outlets and included accessories. The manufacturer provides distinct outlet configurations and downloadable specifications for wine, mixed drinks, juice and cider. A pump or fittings shown in one retailer package are not necessarily standard across the design family.
The inspected sources do not provide a universal cleaning protocol, gasket replacement interval or pressure rating for this open-top tank. Use the instructions supplied for the exact model, keep the lid and seal in sound condition, and do not infer pressure capability from stainless-steel construction. The manufacturer locates its main plant in Ofterdingen, Baden-Württemberg, and states that its products are manufactured there. A Norwegian retailer listing shows one route to the same model outside Germany, but not universal distribution or use.
History
The current Speidel FO1/FO2 product page documents this design, but the sources do not establish when floating-lid tanks were first invented.
Equipment details
Capacity220–910 L Speidel's FO1/FO2 range; individual model capacities vary.
SizeThe linked 300 L model is listed at 139 cm high by 63 cm diameter; this is not a universal tank size.
PowerHand or animal power The listed 300 L kit includes a hand pump for its inflatable lid gasket; the tank itself is not powered.
How you get oneBought, manufactured Speidel offers FO1/FO2 tanks through its order and shop channels; a Norwegian retailer lists a 300 L FO1 package. Availability and fittings depend on model and seller.
CareFollow the exact model's instructions for cleaning, filling and maintaining the lid seal. The inspected sources do not give a universal cleaning schedule or gasket service interval.
Made of
- AISI 304 stainless steel — tank and lid
Specified for Speidel FO1/FO2; details vary across other designs. - Inflatable perimeter gasket — lid seal
Described for many designs in the atlas; a pump is included with the linked 300 L package.
Places
Ofterdingen
Manufacture · Locality evidenceThe manufacturer says products are made at its Ofterdingen main plant. The Norwegian retailer is not treated as a manufacture location.
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Speidel Tank- und BehälterbauForm · Materials · Capacity · Function · Use
Variable capacity tank FO1 / FO2Open-top tank with strengthening rim, vaulted bottom, external litre scale and three legs.
AISI 304 stainless steel, marbled exterior; capacity range 220–910 litres.
Used for storage, maturation and fermentation; listed for wine, juice, cider and industrial applications.
Cited in: A lid that follows the liquid; Variable volume and the seal; A contemporary wine and beverage tank; Selecting and caring for a model
Brewshop NorwayModel example · Dimensions · Accessories · Linked image
Speidel FO1 300L Fermentation Tank with Floating Lid – Complete (Made to Order)Lists a 300 L FO1 with AISI 304 steel, floating lid, pump and accessories.
Model dimensions are listed as 139 cm high by 63 cm diameter.
Product photographs show the tank and lid kit separately.
Cited in: A contemporary wine and beverage tank; Selecting and caring for a model
Speidel Tank- und BehälterbauManufacture · Geography
LocationManufacturer states its products are manufactured at its main plant in Ofterdingen, Germany.
Cited in: Selecting and caring for a model