My main complaint with the 1.5 powder was extreme inconsistency between batches. One batch, which many people were complaining about in the Soylent forums, had a rancid/sour/burnt taste and smell to it. The problem with the formula is that because it has a very bland taste, inconsistency stands out like a sore thumb and your mind works wonders to create an aversion to the whole product. Once I started having the weird tasting Soylent, even the "normal" batches were no longer palatable to me.

Soylent staff dismissed these concerns as "normal variation in a plant based product".