Please take care when describing a food as high carb. It is important to remember there are people on this forum carb counting to calculate insulin dose rather than to minimise carbs eaten.
21g of carbs per 100g is not high when you compare it with bread (about 50% carbs) and grapes.
Apologies, but I think this comment is in itself misleading.
I agree 21% (for quinoa) is not high in relation to bread. [Digression - who thinks quinoa is a relevant substitute for bread or potatoes? A slice of quinoa, a chunk of quinoa??]
But grapes? Where does that comparison come from
@helli? Grapes seem to be 15-16%, depending on the reference source. While that is higher than many fruits (cucumber 1%, tomato c.3%, strawberry c. 6%, bluebs, peaches, plums c. 9%, pineapple c.13%) grapes at 15% are demonstrably lower than banana, c. 20% and not in the same league as bread.
Like you I also see comments about grapes being akin to sugar balls and also don't understand those remarks, which initially misled me until I looked up grapes in Carbs and Cals. I use grapes as a snack when I'm caught having to chase my insulin! Way quicker response than a plain biscuit (c.8-10%), fair bit slower than dried apricots or prunes, c.40-45% and pedestrian in relation to jelly babies, c.95%. I fully agree that comparison between grapes, 15% and sugar, 100% could be dangerously misleading and cause hypos for people new to carb counting or even guestimating.
A further digression: Grapes have a place in a menu; a small qty in a chicken veronique make a great variation on an otherwise potentially bland dish with a very small carb increase overall and because they are being digested in a usually very low carb dish might have negligible effect on many peoples BG.