The following expression was used in an old baking book, "The Modern Baker, Confectioner and Caterer" (1907) by John Kirkland:
The bad results so frequently obtained are generally due to the method of cooking. If the batter is in the least degree too stiff" the muffins are certain to be " blind ".
What state of muffins is expressed to be "blind"?
The book is accessible online here and the above expression is found at page 153 (an original book page).
Thanks in advance.
The same book has another use of the word blind with more explanation:
Care has also to be taken that rolls are not allowed to prove too much, or they fail to retain the neat shape given at moulding, do not open out as they should, and are in fact what bakers call blind.
The recipe you are asking seems to be for what is called a crumpet, which is partially yeast and partially bicarbonate risen. Crumpets are griddle cooked rather than baked, and you get a holey, spongy texture from the 'spring' you get from the chemical leavening agent's reaction. If the mix is too thick you won't get this spring, leaving the dough constrained. So the definition I'd give from these two uses is 'lack of spring'.
Note this term isn't used anymore, as far as I know.
