A little technical knowledge

Here, we are dealing with the oil, the cover, the wick and the wick-holder. But the very first thing we must do is distinguish between candles and oil lights.


This is the name for all sources of light comprising a wick surrounded by a solid burning mass. If it hasn’t got a wick, it may not be called a candle. So a »Roman candle« is not a candle in reality. The same applies for containers or firm covers (e.g. glasses) which, although they have a wick, are filled with a liquid fuel. These are then lights, lamps or lanterns.

Oil lights.

They comprise a solid burning mass with a wick, surrounded by a rigid cover. The designation of »oil light« may only be used if the burning mass exclusively comprises hardened vegetable oil or solid vegetable fat.

Sanctuary oil.

Liquid oil of 100% pure vegetable oil according to liturgical directives. For centuries, this oil was the basis of the eternal light in churches until it was replaced in the 1960’s to a great extent by sanctuary oil candles, which are considerably more practical in handling.
Aeterna is the only manufacturer in Germany to produce such liquid sanctuary oil nowadays.

Sanctuary oil lights.

Eternal lights of hardened vegetable oil cast in plastic covers. They embody the lamp of God and comprise 100% vegetable oil according to liturgical directives, just like the liquid sanctuary oil. They have a guaranteed burning time of seven or nine days, as the case may be.

Composition oil lights.

Not only solid, hardened and unhardened vegetable oils or fats, but also those of animal origin may be used for this. They are mixed with waxes, solid fatty acids or solid hydrocarbon compounds. The share of solid, hardened or unhardened vegetable or animal oils and fats is stated as a percentage and may not be below 30%.

The wick.

In most cases, it is braided from cotton threads. Its condition determines how well and evenly the flame burns. It is matched to the diameter of the candle, the raw materials used and the production method in question. The variety is correspondingly large: each manufacturer has his own specific wicks for each of his products.

The wick-holder.

The important thing is that the wick is always in the middle. In candles, the wick is kept in the middle by the solid body. In oil lights, the wick must be given greater stability, as the share of the liquid burning mass inside the cover is considerably higher. It is achieved by surrounding the wick with paraffin and also by the wick-holder, a small metal plate on the bottom of the wick on the base of the cover.

The cover.

It is transparent or coloured red and mainly made of plastic. Since 1992, the covers of all Aeterna lights have been made of Biocellat, a material which is biologically decomposable in its component parts.

The burning time.

A reliable statement of the burning time is important, in particular in the liturgical area, as the light may not go out and must be replaced in good time. The burning time stated, three, seven or nine days, must be complied with in a closed room measuring at least 25 square metres free of draughts and at a constant temperature of 20°. At Aeterna, random samples from production are regularly tested in a specific chamber. The same also applies for grave lights, the functionality of which we check in a long-term test under concrete weather conditions in the open air.

The storage.

As we know from housekeeping, vegetable oils cannot be kept for ever. The length of time depends both on the treatment with the producer, i.e. with us, and also on the circumstances of the later storage. In production, we treat the raw materials in such a way that a long burning life is guaranteed. We recommend making use of the lights within one year. However, lights which are even two to three years old can still burn perfectly if they are stored cool and dry without exposure to light.