I’m new to baking, so this tip might be well known to everyone – in which case, apologies. I just discovered it the other day.
A British Pound coin is 3mm thick. Two of them stacked measures 6mm.
If you’re making a thin pastry or dough, its thickness is often stated as 3mm (millimetres), or occasionally 5mm.
I find it nearly impossible to measure 3mm using a ruler or measuring tape on my work surface because the first few millimetres are either blank or covered with a metal L-shape bracket. So when I want to measure something of such a delicate and thin height, I just nudge a Pound coin up to it and either eye the comparison or feel the height using my straightened index finger. This worked brilliantly for me when I made Dan Lepard’s Extra-Crispy Rye Breads.
And, yes, I know that coins carry all sorts of germs, so just drop it into a cup of freshly boiled water. Alternatively, smear hand-sanitising gel on it and allow it to air dry before nudging it against the dough.
No more twisting my head sideways and squinting at a ruler!