Both tea and coffee are organic products of vegetable origin that have been used for a long time as natural dyes, due to the dark woody tone that coffee projects many people have tried to dye concrete surfaces with coffee looking for an economical, easy, beautiful and natural way to give color to concrete.
Once while I was looking for ways to create a stain for concrete surfaces I made different tests with coffee as a stain, and although coffee does have the ability to stain concrete, due to the low chemical affinity between the two materials, the resulting stain is of very low intensity and fixation.
Coffee has been known not only as a beverage but also for its dyeing properties, although it has been studied scientifically in other areas, until now it had not been analyzed from its aspect as a dyeing substance.
Tests carried out with coffee to stain concrete
Has it ever happened to you that you look for information on the internet about something that is supposed to work and is easy to do and when you do the test it becomes complicated and you don’t get anything like it?
Well, the same thing happened to me in this case, I found some information, with pictures included, where they gave simple instructions on how to stain concrete with recycled coffee, in the example, they showed a random picture of stained concrete with an even and beautiful color.
Well, in the different tests that I made with coffee, although I could notice that coffee can stain the concrete, it was not a uniform or well-defined color in any of the cases.
It’s a pity that I didn’t take pictures of the tests I did, but the result was really poor, the concrete just looked “dirty” of something, not really tinted.
I tried the stain in several ways, first with water only, when I saw that the color on the concrete was not so visible I tried a much more concentrated mixture of coffee with less water.
The coffee that I used, was an instant coffee of a famous commercial brand, the most granulated that I could find.
Then I did another test of the coffee with little water and a little vinegar to try to get the dye to penetrate more into the surface of the concrete and the result was just as discouraging until I finally discarded the idea of staining the concrete with coffee, for me it does not work.
Why doesn’t coffee work as a stain for concrete?
The fact that coffee works as a stain for other elements such as fabric and wood and does not work as well for concrete is simply due to a principle of chemical affinity between the materials.
Cement is a much less organic material than wood and fabric, coffee has much more affinity with fabric and wood because it is a totally organic element, but not so much with concrete.
If you notice, the acid stain that is used for concrete works very well because they react chemically with the concrete and that is precisely where the functionality of the stain lies.
I can understand the fact that people want to use coffee as a stain for concrete because it is a much more noble element and the “dark brown” stain resembles somewhat the wood, some even justify its use because they can “recycle” coffee to stain concrete, something that does not seem functional to me.
When coffee is used, most of its components have already been extracted through hot water, the remaining material remains wet and does not have the same staining capacity as roasted coffee.
In fact, a roasted coffee concentrated in little water has little capacity to dye concrete, imagine a “recycled” coffee, the idea of using recycled coffee to stain concrete simply does not work logically.
What can you use as a stain for concrete instead of coffee?
Because I was looking for an organic alternative as a stain for concrete, whose result is a color similar to wood, my first option was to try coffee as a stain, but seeing that I did not get good results I had to look for something similar.
I used an acid stain for concrete, in another topic, I explained step by step how I was able to create this stain myself and I was very satisfied with the result.
The stain was created with iron sulfate dissolved in water, a little manganese sulfate and I added vinegar to the mixture to give it the acid touch for better penetration to the concrete.
What is the best coffee to be used as a stain for concrete?
In the case that you want to do the test of staining concrete with coffee, the idea is that you choose an instant roasted coffee, the more granulated the better, and the less proportion of water you add, the more concentrated it will be.
In studies carried out it was determined that in different humidity measurements the molecules responsible for the staining of coffee are affected, the lower the humidity the better the staining properties of the coffee.
This means that roasted coffee, by passing through a special drying process, has better properties to be used as a stain.
Which elements of coffee work as a concrete pigment?
The most interesting aspect of the coffee plant, in this case, is its facet as a pigment. In popular culture, there are references to this compound being used to dye everything from textile fibers to human hair. to human hair.
Physically, the coffee bean already indicates with its color part of its history, since according to certain studies, the color of the bean, or even the lack of it, indicates from the harvesting of unripe beans to excessive drying processes. excessive drying processes.
It has not been possible to determine if the coloring substances of coffee are in the exterior of the beans or in their interior, so it is possible to know to what extent the appearance of the bean is due to the processes to which it is subjected affects the final result of the staining.
There are several studies in which an attempt has been made to identify and classify the compounds in coffee beans that are responsible for the browning reactions.
None of the studies have been completely successful, they have only provided an approximation of which elements of coffee are capable of being used as stains.
Although these studies have determined some very interesting data to be taken into consideration at the moment of taking into account a type of coffee as a dyeing element.