Sizu When you dry a food, only water leaves. Everything else stays: the protein, the sugars, the salt. That one fact lets you work out, before you switch the dehydrator on, how much dried product a batch will give, how many packs it fills and what the label should say. It also gives you a number to watch on the scale, so you know when to stop.
The worked batch
A market-stall batch of plant-based jerky is made from pressed tofu in a marinade. After pressing and soaking up the marinade, the strips on the trays weigh 3,843 g. The solids come from two places:
- 702.3 g from the tofu (after the press has taken its water out)
- 98.9 g from the marinade the tofu took up (its dissolved and suspended solids, worked out from the ingredients’ water content)
Total solids = 702.3 + 98.9 = 801.2 g.
Dry to a target
Say the jerky is dried to 10% water. Then the solids are the other 90%, so:
dried weight = solids ÷ (1 − target water) = 801.2 ÷ 0.90 = 890.2 g
So 3,843 g of wet strips becomes 890.2 g of jerky, about 4.3 to 1. When the trays weigh 890.2 g in total, the batch is at its target. That is how you use a scale to decide it is done.
The target changes the answer
The same 801.2 g of solids weighs more if you stop sooner.
At 5% water it is 843.4 g, at 10% 890.2 g, at 15% 942.6 g and at 20% 1,001.5 g. Heavier is not better value: the extra weight is water, and water is what lets spoilage in. Choose the target first and then plan to it.
From weight to packs and label
At 58 g per pack, 890.2 ÷ 58 = 15.35, so 15 packs with 20.2 g (about 20 g) left over to taste. Fifteen packs of 58 g is 870 g. The label says Net wt 2 oz (56 g), so each pack holds a little more than it claims. Never fill less than the label says.
The book also works out sodium from the marinade’s tamari and rub: about 303 mg per 30 g serving, 13% of the Daily Value. That is arithmetic against the FDA Daily Value for the label, not dietary advice.
What the scale cannot tell you
The scale tells you the batch has reached its weight target. It does not tell you that the jerky is safe to store. Whether it is shelf-stable depends on its water activity, and only a lab test measures that. Until you have one, treat the weight as a production target and store and sell accordingly.
Rule of thumb
Weigh the solids, choose the water target, divide: dried weight = solids ÷ (1 − target). Then work packs, label and price from that number.
Try it with your own batch
The free Jerky Without Meat calculator takes the tofu weight, the press loss, the marinade uptake, the target water, the pack size and the sodium inputs, and gives the dried weight, the packs, the label weight and the sodium per serving. It opens on the batch above. It comes from Vegan Pantry Math, a paperback of marinades, dehydrating, rubs and quick pickles worked out step by step, with 48 recipes.
Weights are the book’s worked example, not a promise for your batch. Weigh your own and follow your local food rules.