Instruct: Classify a given Amazon review into positive or negative sentiment.
Query: Very Concerned

I purchased this machine about 2 months ago. I have made about 10 loaves of the whole wheat and the whole wheat raisin. Every loaf has had a crystalized hard tooth breaking type substance in it. It is like have little rocks or sand in the loaf. I did extensive monitoring of the problem (sifting ingredients to make sure that they were not contaminated,changing the raisins) and identified that it has to do with the baking. The only loaves I had success with were one from a mix and one that I used the "dough" setting and baked the loaf in the oven.