From the time I was very young and just beginning to cook, I always heard about blanching but never heard of parboiling. I learned how to blanch vegetables to prepare for freezing, removing skins from tomatoes and nuts, etc., all pretty standard.
However, in later years I hear the term parboiling quite frequently. Wondering if it was the same thing, I started searching for information. Believe me when I say that there is no shortage of it!
My problem is that there doesn't seem to be any consistent answers. I found answers saying they were the same, that one used the ice bath and the other didn't (but one site will say to use the ice bath when blanching and another will say when parboiling), and even lengthy descriptions of either. What I can't seem to find is anything consistent.
Is it just a case of semantics with the terms being interchangeable? If they are different methods, can anyone give me the true answer of what each is from a credible culinary source?
Best Answer
Both involve boiling water, but there are a number of differences:
blanching has two meanings -- it's mainly used when talking about setting (or enhancing) the color of vegetables, with minimal cooking (only the outermost layer is cooked). As such, it's typically only a few seconds to a minute dip in already boiling water, followed by a shock (dip in ice water) to halt any further cooking. It's often used for vegetables that are going to be eaten raw.
parboiling means that you cook something in boiling water to give it a head start. (Parcooking in boiling water) Typically, the purpose is to cook an item to speed up the cooking time for some following cooking method. (eg, partially cook some items in a casserole so that all items will be done at the same time after baking).
And then we have the overlap case -- when you cook something in water to change the characteristics (other than color) of an item before some other cooking step. For example, we might be trying to extract bitter compounds, or soften a food such that some other processing step can be performed (eg, soften cabbage leaves so they can be used as a wrapper). In this case, you're typically cooking the item more than just superficially, and the pre-cooking results in a different result than you'd simply get by increasing the time of the final cooking (eg, the oil blanch for pommes frites, softening the skin to peel a tomato)
So, to help make a decision on which term to use:
... for other cases, where the step can't be omitted without causing problems in the recipe (eg, cabage breaks because it wasn't softened), or final result (too bitter) ... you can often use either term. You might consider how far 'cooked' the item is after the step if you want to prefer one or the other. (under about 25% cooked, go with 'blanch', if over 50%, go with par-boil)