The problem with liquid chalk
If you have a bottle of liquid chalk nearby, take a look at the ingredients on the back. Chances are that it will have a number of ingredients listed, with at least one by the name of Rosin, Resin, Colophony, Thickener or Scent. Colophony, as this substance is most formally known, is the sap that is extracted from various types of conifer tree. It is a thick, sticky substance used for applications, such as floor polishes and varnish.
What’s Wrong with Resin?
A critical issue for climbers is that the use of resins in liquid chalks means that these resins build up over time on the surface to which they are applied. This is detrimental to the quality of holds, as well as deteriorating the quality of grip in other sports. Holds can quickly become a significantly higher grade as this glass-like resin buildup reduces the friction available.
Instead, opting for a resin-free liquid chalk means the only thing left on holds, is chalk.
Why is Resin Added to Chalk?
Resin is added because it thickens the bottle's contents and reduces the amount of chalk that needs to go into the bottle. It is in effect a cheap filler for liquid chalks. It acts as an emulsifier, but is a very unnecessary one as a single shake is normally sufficient before using a resin-free chalk.
Like the buildup on surfaces, resin can also get left on the hands after use, which presents a skin allergy risk. As such, in the European Union alone, all products containing more than 1% colophony have to be labeled with an allergy warning due to this risk.
(we’ll spare you the image)
All Alcohol is not Created Equal
An extra consideration for climbers who want to minimise their footprint if the type of alcohol in their chalk. There are two types of alcohol that can go into liquid chalks.
The first type, isopropyl alcohol, is the cheapest and by far most commonly used. It is made from propene, a crude oil derivative.
The second type, ethanol, is alcohol made in the more traditional method of from distilling grains. It is a more expensive process (and hence is less commonly used), but is not derived from fossil fuels and is therefore a more natural and sustainable alcohol.
Unfortunately, it is not a labelling requirement to disclose which type is used, so you wont see which is in yours, but chances are it's the former.
Dr Chalk contains zero resin and only uses alcohol made from natural grains, with ultra fine magnesium carbonate for maximum grip.