If you look at occurrences of 'embers' in the source document, several are spelled 'emberses'.
I think these, and 'wembers' are an artefact of an imperfectly executed 'find and replace' which was supposed to change 'ash' to 'ember' and inadvertantly also changes 'ashes' to 'emberses' and 'wash' to 'wembers'.
@AndyT points out further words 'fembersion' and 'dembers' which would result from replacing 'ash' with 'ember' in 'fashion' and 'dash'.
As to why the change was executed; I would hazard that that the 9th Huddersfield version was subject to the change when someone decided that the use of 'ashes' as copied from the Backwoods Cookbook (which @JamesP linked) was inaccurate. Chambers does give embers as 'red hot ashes', but ash as 'dust or remains of anything burnt'. For clarity you would want to make sure people knew to use the glowing bits rather than the grey bits. So the change was possibly made following a critical review of the article.