Place the dried beans in a large bowl and cover with water by at least 3-4 inches, as they will triple in volume. Soak for a full 24 hours, adding more water if needed to keep them fully submerged.
Drain the soaked beans thoroughly.
Transfer them to a food processor along with the garlic, onion, cumin, coriander, cayenne, parsley/cilantro, salt, pepper, baking soda, and lemon juice.
Pulse the mixture until it's finely ground but not a completely smooth paste—a slightly coarse, crumbly texture is perfect. Scrape down the sides of the bowl as needed. Avoid adding water, but if the machine struggles, add 1 tablespoon (15 ml / 0.5 fl oz) at a time, keeping the mixture as dry as possible.
Pour neutral oil to a depth of at least 2 inches in a large, deep saucepan over medium-high heat.
Heat the oil to approximately 350°F (175°C). A small pinch of the falafel mixture should sizzle immediately when dropped in.
Scoop heaping tablespoons of the mixture and form them into 1-inch balls or small, slightly flattened patties. Carefully place them in the hot oil, frying in batches to avoid overcrowding the pan.
Fry for 3-5 minutes, turning occasionally, until they are deep golden brown and crispy on all sides. Use a slotted spoon to transfer the cooked falafel to a paper towel-lined plate to drain.
Serve immediately or at room temperature.
Keep the mixture as dry as possible.
Adding too much water will cause the falafel to fall apart in the fryer. The mixture should be crumbly but hold its shape when pressed together.