People love absorbent coasters. They are some of the most functional home accessories that you can purchase. Acting as a shield, a barrier against stains, they soak up the moisture from a sweaty glass, and hold it within themselves, keeping water damage from spreading to your possessions. However the problem is who protects the coasters from those stains? Can you purchase a permanent set of absorbent drink coasters, or are you relegated to the fleeting functionality of less sophisticated disposable models.
First a quick overview of disposable coasters; these consist of paper, cork, sponge, and other low cost material coasters. Their purpose is to be cheap, and effective, once or twice, and then to be tossed. This is the most common choice for a bar or restaurant, because they are easy to replace and purchase in bulk. You can even get them printed up with a particular business logo or graphic.
The problem with these coasters is that they get soggy and nasty pretty quickly. They are also obviously cheep, and don't have much decorative style to them. In a bar, where everything is disposable and made to order this works, but in a home, which is supposed to be your custom environment, it can be a little embarrassing.
The alternative to these temporary accessories are the new absorbent sandstone and slate coasters which are available. These coasters are made from natural stone materials, which have existed since the earth was formed. Natural properties in these materials, allows them to absorb the moisture from a liquid spill or drip, taking the water into its pores, and holding it inside of the stone. While the water is trapped in the stone, air can and does still reach it, and this causes the liquid to evaporate away.
These stone coasters are great, because they can theoretically last forever. The water goes into the coaster, but it will always evaporate away, without causing much damage to the piece.
The problem is that stone is just a natural material, and sometimes, it can stain. When a colored liquid such as juice or sauce falls on the surface of the sandstone, suddenly that absorbent property is a liability, because it will allow the stain to soak down past the surface of the stone, discoloring it from the inside.
If a staining agent does fall on your coasters there are certain things you can do. Soaking the stone in warm water will often allow you to extract the coloring agent. You can also use heat to try and melt the agent. These methods will be most effective, by far; if they are done immediately after the stain occurs.
Another absorbent alternative is to purchase slate coasters. Slate is another natural stone, and it does have absorbent properties, however slate is less absorbent than sandstone, cork, paper, or just about anything else out there. When a wet glass is placed on a slate coaster, drips of water will fall on the surface and sit there, slowly seeping into the stone. It won't be immediate, but it will have enough suction to keep the water from spilling off over the side of the coaster onto your furnishings.
The fact that they are less absorbent means that they are also resistant to stains, and can survive staining agents much better, and for a much longer period of time, than most of their counterparts.
Absorbent coasters are some of the most useful and functional accessories that are available for your home. They can protect your possessions, while still being stylish, elegant, and customizable. However they do have several drawbacks, most notably of which is their ability to get stained by certain liquid agents. This can make some absorbent coasters more permanent then others. In the end, you will have to balance functionality with durability, to find the perfect set for your situation.