Lighting wine cellars: the sealed tubular luminaire for wine

Lighting a cellar or a winery is no trivial matter. The environment combines constraints that most ordinary luminaires cannot withstand: very high humidity, condensation, fermentation vapours, jet washing and the handling of barrels. Added to this is a requirement specific to wine: controlling the light spectrum to which the harvest, the vats and the bottles are exposed. The sealed tubular luminaire answers both families of constraints at the same time. Here are the technical criteria to know before choosing.

An environment that puts luminaires to the test

Permanent humidity and condensation

Cellars and wineries are deliberately kept at a high humidity level, essential for preserving the wine and limiting evaporation from the barrels. This humidity, often made worse by an underground floor or run-off, is the enemy of poorly protected devices: infiltration through cable glands, corrosion of contacts, condensation in the diffuser. This last point is regularly underestimated: internal condensation forms because of the temperature difference between switching on and switching off, fogs the diffuser, then damages the electronics. Luminaires designed for these atmospheres include a pressure-balancing membrane or valve, which lets water vapour out without letting liquid water in.

Corrosive atmosphere and cleaning

Fermentation vapours, alkaline or chlorinated cleaning products, traces of sulphur dioxide and jet washing require resistant materials. Housing, seals, screws and end caps must withstand these stresses without deteriorating. Hence the choice of stainless steel end caps and screws, a polycarbonate or PMMA diffuser rather than glass, and seals that withstand repeated washing cycles.

Impacts and handling

A winery is also a mechanised workplace: pallet trucks, forklifts, moving barrels, pumping hoses. The luminaire must withstand impacts, which is expressed by the IK rating. At low mounting heights, a high IK rating determines durability. Same logic as in livestock buildings: see our article on LED poultry lighting, another environment where sealing and corrosion resistance decide the real lifetime of the equipment.

IP67, IP69K, IK10: what these ratings guarantee

The IP rating has two digits: the first describes protection against solid bodies and dust, the second protection against liquids. Contrary to a widespread belief, these levels are not strictly cumulative. A luminaire can be qualified for temporary immersion without being qualified for high-pressure jets, and vice versa, which explains why both statements appear separately on data sheets.

| Rating | What it covers | Typical use in a winery |

| --- | --- | --- |

| IP65 | Dust-tight, resistant to water jets from a nozzle | Acceptable minimum in a dry cellar |

| IP67 | Dust-tight, temporary immersion according to the standard in force | Low areas, underground cellars, run-off |

| IP69K | High-pressure, high-temperature jets, according to the standard in force | Vat room, harvest reception, areas cleaned with a pressure washer |

| IK10 | Highest level of impact resistance on the IK scale | Circulation aisles, low mounting height |

The practical rule: IP65 is a floor, not a target. As soon as there is mechanised washing or run-off, aim for IP67 or IP69K. For a digit-by-digit reading of these ratings, see our dedicated article: definition of IP and IK ratings.

Why do people talk about 270 nm?

The figure often comes up in technical discussions about cellars and deserves a precise explanation, because it does not refer to working light. The visible spectrum extends approximately from 380 to 780 nm. Below 380 nm begins the ultraviolet range, divided into UV-A, UV-B and UV-C. A wavelength of 270 nm lies in the UV-C band, and therefore outside the visible range: it lights nothing for the human eye.

If this value is quoted, it is because it lies very close to the absorption maximum of nucleic acids, around 260 to 265 nm. This is what makes UV-C sources effective for microbiological inactivation, and it is in this capacity that the subject appears in the wine sector: treatment of surfaces, vats or air, as part of winery hygiene. This is a disinfection function, separate from the lighting function.

The link with wine works the opposite way from what is sometimes assumed. Wine is photosensitive: under the effect of short wavelengths, riboflavin acts as a photosensitiser and triggers the degradation of sulphur-containing amino acids, the origin of the defect known as light-struck taste, with its notes of cooked cabbage or wet dog. Whites, rosés and sparkling wines are the most exposed, especially as they are often bottled in clear glass. The radiation most involved is ultraviolet and blue, that is, the short part of the spectrum.

The practical conclusion is twofold. Working lighting in a cellar must have no ultraviolet emission: a quality white LED produces none by design, unlike certain traditional sources. This precaution is necessary but not sufficient, and this is the point that most documentation passes over in silence: a white LED is obtained from a blue chip emitting around 450 nm, covered with a phosphor. It therefore retains an emission peak in the blue, that is, in the second band implicated. What really protects the wine comes down to three combined levers: a warm shade, which reduces the relative share of blue for the same flux, a cumulative dose controlled by presence detection and zoning, and keeping the bottles covered whenever possible. In long-term ageing areas and for wines bottled in clear glass, amber shades, which eliminate most of the blue emission, deserve to be examined with the design office. And if a UV-C treatment is used for hygiene, it belongs to dedicated equipment, separate from the lighting, interlocked and used when no one is present and the wine is not exposed. Combining the two functions in a single device would be a design error.

Well-designed winery lighting is not judged only in lux: it is also judged on what it does not emit.

Why the tubular shape is the right answer

The tubular geometry answers the constraints of the winery. The sealed tube delivers even light along its whole length, which suits the aisles between rows of barrels, the corridors of the vat room and narrow circulation routes. Its cylindrical body, smooth and closed, traps neither dust nor moisture and rinses clean in one pass.

The diffusion angle, expressed in degrees, deserves attention. A widely diffusing tube, of the order of 270 degrees depending on the model, lights the floor as well as the walls and the top of the storage: dark areas recede and perceived uniformity improves in a narrow, high volume. Ceiling-mounted, wall-mounted on concrete or suspended on cables, installation remains simple, including in renovation on existing supply points.

The two suitable luminaires in our range

The REXSHOCK TUBULAR IP anti-corrosion tubular luminaire is the reference to choose for cellars and wineries. Designed for corrosive atmospheres, it is offered with a PMMA diffuser rated IP69K or in polycarbonate rated IP67, with an IK10 rating. The manufacturer states it to be resistant to ammonia and sulphurous vapours, fitted with 316L stainless steel end caps and an anti-condensation depressurisation valve, precisely the critical point mentioned above. As no material is permanently immune to ammonia, this resistance is assessed on the basis of a declaration of chemical compatibility from the manufacturer, in relation to the actual concentration and duration of exposure on the site. Its characteristics: 130 to 150 lm/W, 20 to 60 W, 2,600 to 9,000 lm, lengths from 552 to 1452 mm in 75 mm diameter, L90 flux maintenance beyond 54,000 hours and glow-wire resistance at 850 °C. Its range of lengths covers a vaulted cellar corridor as well as a long aisle of barrels.

The REXHALO FOOD IP69K food processing luminaire completes the range for high volumes washed with a high-pressure cleaner: stainless steel vat room, harvest reception area, press room. This circular luminaire is certified IP69K and IK10, with no rough edges or sharp angles to avoid bacterial stagnation. It states 160 lm/W, 50 to 240 W, 8,000 to 38,400 lm, 4000 K and 70,000 hours at L80B20, with a declared resistance to 100 bar and 80 °C. Where the tubular luminaire deals with linear areas, it deals with large surfaces at great heights.

On reading the L70, L80 and L90 notations, our article assessing the reliability and lifetime of LED lighting details the method.

Finding these solutions in the Vineyards and cellars range

The luminaires selected for the sector are grouped in the Vineyards and cellars range, attached to the Food processing family of the industrial catalogue: sealed tubular luminaires and washable luminaires for cellars, wineries, vat rooms and bottling areas. Each reference is offered on quotation, after validation of power ratings and layouts.

Designing the installation, not just choosing a luminaire

Choosing the equipment is not enough. Three parameters decide the result: illuminance, sufficient for working and reading labels without overexposing the bottles; uniformity, written U0, which determines the comfort of moving between high, closely spaced rows; and finally management, because presence detection and zoning reduce consumption and the cumulative light dose received by the wine. These parameters are checked by calculation before the works, not afterwards.

• Adapt illuminance zone by zone rather than a single level.
• Aim for good uniformity in the aisles, including at the end of rows.
• Rule out any source emitting in the ultraviolet, and favour a warm shade that reduces the share of blue.
• Combine presence detection and zoning to limit the cumulative light dose.
• Check accessibility for maintenance in confined volumes.

Frequently asked questions

Which IP rating should be chosen for lighting a cellar or winery?

IP65 is the acceptable minimum in a dry cellar. As soon as there is run-off, heavy condensation or mechanised cleaning, choose IP67 for temporary immersion or IP69K for high-pressure, high-temperature jets. An IK10 usefully completes protection in handling areas.

Does light really damage wine?

Yes. Prolonged exposure to short wavelengths, ultraviolet and blue, triggers a photochemical reaction involving riboflavin and sulphur-containing amino acids: this is the light-struck taste, with its notes of cooked cabbage or wet dog. Whites, rosés and sparkling wines in clear bottles are the most sensitive.

Does a white LED emit ultraviolet?

No, a white lighting LED emits no ultraviolet by design, unlike certain traditional sources. That is not enough to declare it without effect on wine: a white LED combines a blue chip emitting around 450 nm and a phosphor, so it retains a peak in the blue, which is the second band responsible for light-struck taste. The reasoning must focus on the shade chosen, the warmer it is the lower the share of blue for the same flux, and on the cumulative dose received by the bottles. Check the spectrum and the colour temperature on the data sheet of the luminaire chosen, and have the long-term ageing areas assessed by a design office.

What does a wavelength of 270 nm correspond to?

It lies in the UV-C band, outside the visible spectrum, close to the absorption maximum of nucleic acids. It is a wavelength for disinfecting surfaces, vats or air, never for lighting an occupied room. It belongs to dedicated equipment, separate from the working lighting, and must be kept away from exposed wine.

Having your installation sized

Sizing the lighting for a cellar or winery requires an illuminance and uniformity calculation zone by zone, a choice of IP and IK ratings consistent with the cleaning procedures, and a check of the spectrum chosen. Get in touch with our technical partner, the Luminance-Consulting agency, a lighting solutions consultancy since 2013. It carries out photometric studies in DIALux, audits of existing installations and checks of compliance with the applicable standards.

Luminance Consulting · 1 Route de Bartres, 65100 Adé, France. For a cost estimate of the luminaires, contact the Rexylum team; on the value of a preliminary study, read why carry out a photometric study before purchase.