Term for insufficient development of the grapes, which manifests itself in uneven size and insufficient ripening of the berries. It is a manifestation of trickling. The most common cause is cold, rainy or otherwise bad weather during the flowering phase of the vines. However, other factors such as nutrient deficiency, especially of boron, can also play a role. Usually, there are many small, green and hard berries (shot-grain berries) that remain unripe. However, the berries can also ripen later (than the normal berries) with then high sugar but low acid content. Certain grape varieties, clones or rootstocks are particularly susceptible to trickling and small berries due to genetic disposition. These include Cabernet Sauvignon, Gewürztraminer, Sangiovese, Zinfandel and Zweigelt.