noun
foaming; frothing; lathering
The state or process of forming foam, bubbles, or lather. Often used for soap, beer, or agitated liquids.
See also: 泡立つ (あわだつ)
この石鹸は泡立ちがいい。
This soap lathers well.
ビールの泡立ちがきめ細かい。
The beer has a fine, creamy head.
泡立ち is the noun form of the verb 泡立つ (to foam, to froth). 泡立ち refers to the foaming itself or the quality of lather, while 泡立つ describes the action.
Compound of 泡 (awa, 'bubble, foam') and 立ち (tachi, the continuative form of 立つ, 'to stand, rise'). Literally 'foam rising'.