Discover the connection between walnuts, onions, coffee grounds and Easter
This week we celebrate Easter and for most of us that means a hearty breakfast of eggs awaits us on Sunday. Whether it's the resurrection of Jesus Christ, new beginnings, the end of Lent or the start of spring that we're raising a toast to, the brightly colored eggs are simply part of the occasion. Where exactly the tradition of egg dyeing has got its origin is not entirely clear, but it is known, that in the Middle Ages people hard-boiled eggs during Lent to prevent them from spoiling and dyed them with onion skins or beet to distinguish them from fresh eggs.
Today, Easter eggs are often dyed in the industry with synthetic substances such as azo dyes, apart from organic eggs, which may only be dyed with natural dyes and also only during Easter. Natural dyes include various plants such as madder, dyer's chamomile, blue wood, and marigolds, as well as a wide range of coloring foods. For example, spinach or parsley can be used for green colorings, beet for red colorings, red cabbage for blue or purple tones, and carrots, turmeric or caraway for yellow shades. Of course, this selection is only a small part of the whole list, which also includes tomatoes, grapes, peppers and many other foods.
In order to obtain a colorant from the food, it can be boiled, for example, because the decoction that remains has coloring properties. The longer the cooking time and contact with the egg, the more intense the color. The eggs can be boiled during the dyeing process, but the color intensity can be determined more specifically if the eggs are precooked, because in that state they are placed in the decoction only as long as they need to obtain the desired color intensity. In this case, the already cooled broth can also be used. The dye can also be extracted with solvents such as acetone or methanol.
Food is still suitable for dye extraction even if it is no longer completely fresh. Among other things, dried onions or vegetables with small blemishes that are discarded even before they reach the market, could be saved from the trash. We have often expressed in our magazine that we not only want to reduce food waste, but also put residual materials that have had no apparent use for a long time to a new purpose.
Therefore, in the following we would like to discuss residual materials that can be used as dyes due to their coloring properties.
Walnut shells
In mid-February, we introduced you to the many
uses of walnut shells . The dye "juglone", which is contained in the outer green fruit shell, can color not only fabrics, but also the shell of eggs in various shades of brown. In order for the dye to be used throughout the year, the shells are dried or ground into powder.
Coffee grounds
Coffee grounds, which are left over after making coffee and end up in large quantities in the garbage, can serve as a dye for Easter eggs. It produces a light brown shade similar to that of brown eggs, which is why white eggs should be used. However, it is also possible to boil the coffee grounds together with red onion skins, which give the brew a more intense, darker color. This can even create dark, chocolate-brown colors. For more innovative uses of coffee grounds, see our article
innovative products from recycled coffee.
Onion skins
As early as the Middle Ages, people dyed eggs with onion skins. Onion peels can not only be used to supplement a brew made from coffee grounds, but can also be used independently as a dye. Both red and yellow onion peels are suitable for this purpose. Red peels produce red shades, as expected, and the palette of yellow onion peels ranges from yellow to orange to brown.
To ensure that the natural colors adhere particularly well to the eggs, vinegar can be added to the dye obtained: Eggshells have a porous surface, i.e. they are interspersed with pores in which the color particles adhere. If a little vinegar or another acid is added to the natural dye, the colors become more intense, as the acid slightly dissolves the calcium carbonate, of which the shell is largely composed, and thus increases the surface area. It should be noted, however, that too high a pH value has negative effects. For example, if pure vinegar with a pH of 3 is used, it will react with the calcium carbonate to form carbon dioxide, which will detach from the peel in the form of bubbles and prevent the peel from coloring evenly. In extreme cases, the peel may even dissolve completely as the calcium carbonate is consumed during this reaction.
Easter shows us that circular economy can be integrated into a wide variety of aspects of our everyday lives. Even the dyeing of eggs can be made sustainable and contribute to reducing food waste.
In the coming months, we will continue to introduce you to alternative uses of natural raw materials and residues in LEROMA`s magazine. Raw materials can be processed into colorants, flavor enhancers, thickeners, or even natural granules for the cleaning industry or a low-cost filler. In addition, an article will soon be published that deals more intensively with
natural colorants that can be used in the food industry.
We wish you happy Easter days and invite you to have a look at our magazine next week as well.
Let’s simplify the future of change!
