Reference for Shabbat 287:2
מאי לאו לרצון דניחא ליה שלא לרצון בסתמא ומה זיתים וענבים דבני סחיטה נינהו שלא לרצון ולא כלום תותים ורמונים דלאו בני סחיטה נינהו לא כ"ש
it [the milk] is unclean, whereas if one lets blood as a remedy it is clean. Said they to him: Let baskets of olives and grapes prove it, for the liquid that exudes from them with [their owner's] desire is unclean; without [their owner's] desire, is clean. Now does not 'with desire' mean that he [the owner] is pleased therewith;<span class="x" onmousemove="('comment',' I.e., from his explicit statements we understand that he is pleased therewith. — It may be observed that where fruit is kept for its juice, its exuding is regarded as in conformity with the owner's desire, whether he actually wanted it just then or not. ');"><sup>3</sup></span> whilst 'without [his] desire' means that it [the purpose] is unspecified?<span class="x" onmousemove="('comment',' In which case it is clean, because it is not regarded as a liquid. This must at least represent the view of R. Judah, whose range of liquids is more restricted than that of the Rabbis. ');"><sup>4</sup></span>