Always feel your materials. The untrained hand can’t tell you much, but after years of experience your hands can tell you a great deal about a material.

If you are developing a new material, your hands can tell you if it needs a little clay added, or silica fume, or it is too coarse or lacking fines etc.

Take for example pumpability: a dilatant material flows by itself, self-levelling and de-airing, but you can’t pump it. Your hand tells you this, if you squeeze it, it goes hard. Another material may not flow at all, it has a yield value. Squeeze it. If it all squirts out of your hand it is pumpable, if the coarse particles stay behind in your hand, it is not pumpable.

If you want to develop user friendly materials, you must use your hands to feel them.

A mixer does not give you much feedback.