To mark an ingredient as being a member of a certain inventory group (as defined by your operation), you must create an “inventory group” category. To do this, go to the "Categories" page and click the + icon. Next, enter the category name as “inventory group” and set the “item type” to “ingredient”.
Once this category is created, add each of the inventory groups that you would like to have in your category.
Once all category values have been added, you are ready to tag your ingredients. To do this, go into an ingredient’s page and click “show”. Next, click “Add Tag” and enter the appropriate ingredient group tag.