3,416. Preparing the Produce for Eating
Hilchos Maaser 5:14
When a person cooks, boils or pickles produce, the obligation to tithe it takes effect. If one smokes produce until it is ready to eat, there is a question as to whether it must be tithed.
Hilchos Maaser 5:15
If someone buries his produce in soil, straw or manure before preparing it for eating, the obligation to tithe it does not take effect.