I had so much fun researching this topic and not because it is intrinsically funny, but more because it brings out the major ‘What the F… is that’ in most people. For example, in 2016, ABC’s Beth Lipton asks, ‘What the Heck is Nooch and Why is Everyone Talking About it‘. Thug Kitchen (2014, p 10) in their section Dropping the Knowledge (Weird Fucking Ingredients) say of Nooch that it is ‘some level 7 hippie shit’. Eat This, Not That, takes us a little further with, ‘What the Heck is Nooch‘ before saying it has been called ‘hippie dust’ or ‘yeshi’ (a word whose origins are Ethiopian). Huff Post’s contributor, Maria Rodale gets us some way to an answer by asking ‘WTF is Nooch – and other Vegan Lingo Explained’ (emphasis mine). However, it would seem that Nooch (Becky Hughes, 2020) has undergone a cultural change of late and what was once termed ‘hippie’, or ‘vegan’ is now seen as mainstream. Hughes headlines ‘Nutritiional Yeast is for Hippies. ‘Nooch’ is for Everyone. Nutritional Yeast (the origin for Nooch) is now firmly located in the alternative ‘other’ of weird foods.
OK, first what it is not. Nooch, or nutritional yeast, is not brewers yeast. Brewers yeast is activated yeast, nooch is deactivated yeast. Nor is it baking yeast – that is dry active yeast – again nooch is deactivated. Finally, it is not yeast extract, you know, Vegemite or Marmite. No, although they are both made from much the same stuff, saccharomyces cerevivsiae, yeast extracts are made from leftover yeast after commercial beer brewing, while nutritional yeast is generally sourced as a yeast grown on molasses, beets or sugar cane. Once fermented, the yeast is harvested, washed, pasteurized and dried. The last two steps deactivate the yeast’s leavening ability, its main difference from active dry yeast or Brewer’s yeast.
Nutritional yeast is a better source of nutrition than yeast extract, and far less salty. Although said to be high in the B vitamins, the process of production means that Vit B12 needs to be added to most retail versions of nutritional yeast. Savvy Wealth Media produced the following table of comparison (spelling mistakes all theirs!) when talking about the nutritional value of nutritional yeast versus yeast extract:

Nutritional yeast has been around for a long time. Attributed first to the ancient Egyptians, it was designed in modern times by Bragg Live Foods Inc. which has been around since 1912 (Savvy Wealth Media). However it was not until 1950 that inactive dried nutritional yeast flakes hit the shelves in the form of Red Star yeast and not till 2007 that its earliest entry can be seen in the Urban Dictionary (although the Cambridge Dictionary did not manage this till 2021), where the abbreviation is attributed to the Post Punk Kitchen cooking programme fronted by Isa Chandra which ran from 2003-2005 in New York.
But why would anyone eat such a dull sounding thing as ‘inactive dried nutritional yeast flakes’? Well, a lot of people wouldn’t, just as a lot of people do not like yeast extracts. Nutritional yeast is said to have a cheesy tang that gives an umami flavour to whatever it is used with. This umami flavor profile, brings both savory and salty flavors to foods that are mild in taste. It resembles a nutty, cheesy taste that’s similar to parmesan and comes in flakey and powdery forms that makes it easy to sprinkle on pretty much anything (Fritinancy, 2017). It can be used for all sorts of things – to replace Parmersan, blended with vegetables to create dips, used to flavour soups and stews and, I am told, goes exceptionally well on popcorn. There is even a book, The Ultimate Uncheese Cookbook’ dedicated to it.
LiveKindly and Vegetarian Zen both provide easy online recipes which use Nooch in various ways. Fiona Donnelly in the Guardian of 21/9/2022 gives suggestions on how to cook with it, but it is Kim from Insanely Good who, I think, provides the best range of recipes for beginners to try in her 25 Easy Nutritional Yeast Recipes (How to cook with Nooch). Below is her recipe for Easy Vegan Pesto – which takes just 5 minutes, she says!

From: Insanely Good Recipes
Weekly Recipe