Introduction
- The melacha of ‘lisha’ (or ‘lash’), kneading, is the next melacha in the ‘sidura dePas’, the sequence of melachos involved in making bread. Going forward we shall reference the lisha, lash and kneading interchangeably when referring to this melacha.
- We previously quoted the Yerushalmi that this melacha took place in the making of the lechem hapanim, and from this we learn that one may not do lisha on Shabbos.
Paramaters of the Melacha
- The melacha of lisha applies in circumstances where the following three conditions are met:
- One is combining two different substances
- At least one of these substances is either:
- made up of small pieces such as flour, or finely cut vegetables or eggs,
- thick, such as jam
- As a consequence of combining the two substances, they form a single mass (for ease we may refer to this as a ‘dough’). This can simply be because the substances are sticky and need not necessarily be because one of the items is a liquid. For example, it is forbidden to mix honey and cheese, or butter with cocoa powder. (SSK 8:1)
Lisha with One Substance
- As a consequence of the first condition above, there is no prohibition of lisha when mashing a banana until it has a doughy texture, so long as one does not add further substances to it (however, mashing a banana is generally prohibited under the melacha of tochen, though is permitted if done in an unusual fashion, for immediate consumption, for one who will struggle to eat it otherwise).
- Some permit pressing together crumbs of a previously baked good with a uniform makeup such as challa (as opposed to eg doghnuts which have pockets of jam inside), treating these as one substance. However, not all agree with this as the moisture within the crumbs is what enables them to combine (so it could be considered as if the moisture is a second substance) (SSK 8:3, fn13).
When the Substances Do Not Form a Single Mass
- As a consequence of the third condition above, there is no prohibition of Lisha (Lash) on Shabbos when adding oil, vinegar, mayonnaise etc to larger pieces of fruit or vegetables, such as when making fruit or potato or lettuce salad, as this does not combine the pieces into one mass.
- Similarly there is no prohibition to mix different powdered substances like sugar, cinnamon or cocoa powder together, as there is nothing present that combines these into a single mass (SSK 8:4)
For Immediate Use
- Unlike by borer and tochen, the melacha of lisha applies even if one is doing it immediately prior to one’s meal. (SSK 8:2)
