If your soup tastes bitter and you haven’t added any bitter ingredients, it’s probably your squash. If there’s a sudden hot spell, cold snap, or pest infestation when your squash is growing, it can make the squash produce bitter chemicals. Poor stressed out squash! I’ve never personally had this problem, but if your soup is really bitter, throw it out. It’s frustrating to toss dinner after all your hard work making it but it’s better than spending the entire night in the bathroom regretting it. FACTS.