I have been experimenting with RDT and the results are interesting. Sorry it is a long video and I’m sure not everyone will agree with my conclusions. It is also a small sample size but it’s clear that there’s more to explore.
The study found that RDT reduces charge and at 20 microlitre/gm the charge is zero. It also increases extraction times by 50 %. The claim is that this is because there are less aggregates due to less charged particle.
RDT can both positively or negatively impact flavours. But WDT+RDT produces better flavours when compared to RDT alone. The study did not include WDT.
The effects of RDT are independent of WDT. And it varies depending on the amount of water, burr and roast colour. These variables determine whether the effects of RDT are positive or negative.
The effect on extraction time is also dependent on these variables.
when the beans are left to soak, the effect of RDT on extraction time is reversed (if it had previously increased it)
It seems to me that once the water is absorbed by the beans, the effects are lost. Therefore it’s the water on the surface of the bean that is important. This surface water modulates the interaction between the coffee beans and the burr and influences the way the beans break.