By Elska á Fjárfelli and THL Fionnghuala inghean Diarmada
Blanching: does it mean soaked, or scalded?
According to the dictionary blanch comes to Middle English by way of the Old French blanchir, from blanc for white, and is of Germanic origin. As a verb, blanching can mean to make white or pale; to bleach by extracting color; to whiten a plant by depriving it of light; to pale from shock, fear or a similar emotion; or to prepare vegetables for freezing or further cooking by briefly immersing in boiling water. In modern English blanch and scald are synonyms, both meaning to boil briefly. 
In many medieval recipes, on the other hand, blanching is mentioned in combination with soaking in cold water. So why the difference?
Blanching as a cold water treatment could fit in the medieval preference for white foods. Golden foods, like those colored with saffron, were supposed to ensure happiness, white foods were supposed to achieve purity – and sharp, bitter, and black foodstuffs were to be avoided.  Soaking would lighten the color of foods by leaching out part of its colorants (like making tea) to then be disposed of separately, and could be how the technique of blanching got its name.
In the process of making marzipan from almonds, the process also seems to have another function: blanching almonds by soaking slightly hydrates the nuts. With much longer travel time from farm to table, and less ideal storage (no ziplocks or vacuum seals), medieval nuts like almonds were likely to contain less moisture than their modern counterparts and cold water soaking would counteract some of that loss of moisture. This hydration can make a difference in the making of marzipan, as dry crumbly almonds do not tend to stick together as well and would need lots more grinding (and rosewater) than their soaked counterparts. And while our modern almonds are likely to be much fresher, my scalded almonds did not make the sticky marzipan I grew up with either, putting me on this quest to figure out the why.
Sample recipes defining blanching as soaking in cold water:
Le Ménagier de Paris, 14th century: 
“Another porée of new chard […] But still greener and better is that which has been sorted, then washed and cut up very small, then blanched in cold water.”
A book of cookrye. Very necessary for all such as delight therin’, gathered by “AW”, 1591:
“How to make a good Marchpaine. First take a pound of long smal almonds and blanch them in cold water, and dry them as drye as you can, then grinde them small, […]” 
Elinor Fettiplace’s Receipt Book, 1604: Spurling
“To make french biskit bread: Take one pound of almonds blanched in cold water, beat them verie smale […]”
The Complete Practical Cook by Charles Carter, 1730: 
“To make an Almond Cake. […] next morning rub it through a cource sive blanch 2 pounds of Almonds in cold water beat them with Orenge flower water very fine […]”
Other 17th and 18th century cookbooks mention both scalding and blanching in combination of preparing almonds:
The Queens Closet Opened by W.M., 1655:
“To make Marchpane to Ice and guild and garnish it according to Art. Take Almonds and blanch them out of seething water […]”
The Cooks and Confectioners Dictionary; Or, The Accomplish’d Housewifes Companion by John Nott, 1723:
“8. To make Almond Bisket. […] having ready half a Pound of blanched Almonds, in cold water, beat them well […]”
“11. Almond Cakes. Beat a Pound of Almonds blanch’d in cold Water […]”
“19. To Make White Crisp’d Almonds. Scald and blanch your Almonds as before […]”
“29. Another Way. Scald and blanch you Almonds, pound them in a Mortar as before […]”
“109. Blanc-Mangers. Blanch a Pound of sweet Almonds in scalding Water, […]”
There seems to be a predilection in early cookbooks for using the term blanching when indicating the use of cold water, and the term scalding for when hot water is used, (Steinhardt) in the processing of almonds. When both blanching and scalding are mentioned together, blanch could conceivably mean the quenching step of submerging the scalded almonds in cold (iced) water. This usage of the word blanch in connection with a cold water bath is also found in the 1591 A Book of Cookrye in recipes using ingredients other than almonds:
“A Pudding in Egges. Take and boyle your Egges hard, and blanch them, […]”
“How to bake pyes of Calves feet. Take Calves feet and wash them, boyle and blanch the haire of them, […]”
As the modern definition of blanching has come to mean only a brief immersion in boiling water followed by an icewater bath, this could indicate a change of definition of the word blanch from cold water soaking in medieval times to our modern brief boiling water immersion followed by a cold dunk. The varying use of the word blanch in the 18th century Cooks and Confectioners Dictionary by John Nott – sometimes meaning cold water soak, sometimes indicating the quenching step of scalding, and sometimes even scalding alone – seems to support this theory.
Have more recipes? While there are many recipes indicating to blanch or scald your almonds (and vegetables), most do not indicate how. The ones that give more information are in the minority, so if you have one I did not list here please do not hesitate to share. I’d love to see how it fits this pattern!
Adamson, Melitta Weiss. Food in Medieval Times. Greenwood Publishing Group, 2004.
Day, Ivan. The Complete Practical Cook by Charles Carter, London, 1730.
Greco, Gina L. & Rose, Christine M. The Good Wife’s Guide: A Medieval Household Book. Ithaca NY: Cornell University Press, 2009.
Nott, John. The Cooks and Confectioners Dictionary; Or, The Accomplish’d Housewifes Companion. C. Rivington, 1723.
Spurling, Hilary (1986) Elinor Fettiplace’s Receipt Book, Penguin Books.
Waks, Mark & Jane (transcribers) A Book of Cookrye, by A. W., London, 1591. Originally published 1584. STC 24897 — Early English Text microfilms reel 1613:9
W. M., The Queens Closet Opened. Incomparable Secrets in Physick, Chirurgery, Preserving, Candying, and Cookery ; as They Were Presented to the Queen, 1655.
 Adamson, 199
 Greco, 279