Brining Calculator — Fick's Diffusion Law for Wet and Dry Brines
Recipes say 'brine 4 hours' like it's a constant. It isn't. Brine time scales with the SQUARE of the protein's thickness — a 40mm pork chop takes 2.5x longer than a 25mm chop at the same salt level. Chicken breast absorbs salt twice as fast as beef. This wizard applies Fick's diffusion law to your specific protein, thickness, and salt concentration, then flags under-brine (surface-only seasoning) and over-brine (mushy texture) windows. Wet brine and dry brine both supported; cooking adjustments after.
- 1Protein
- 2Method
- 3Goal
- 4Schedule
- 5Cook adjust
Why "brine 4 hours" is almost always wrong for your specific cut
Quick answer: brine time is not a fixed clock reading. It scales with the SQUARE of thickness and INVERSELY with salt concentration. A 25mm chicken breast at 5% salt brine takes about 1.5 hours to hit 0.5% internal salt. A 40mm pork chop at the same brine needs ~4 hours. A 100mm pork shoulder needs 24+ hours. The same recipe telling all three "brine 4 hours" over-brines the chicken, correctly brines the chop, and barely seasons the shoulder surface.
Fick's first law of diffusion governs how salt (and water, sugar, flavor compounds) move through protein tissue. Concentration gradients drive diffusion; distance squared gates it. The wizard applies this physics to your specific inputs and returns a concrete time, flagged against the under-brine and over-brine windows for your protein type.
Wet brine vs dry brine — when each wins
Quick answer: wet brine is faster and adds moisture (via salt-driven protein swelling that traps water). Dry brine is slower but gives deeper flavor, better crust on high-heat cooks, and near-impossible to over-salt. Pick wet for thin lean cuts with short brine windows; pick dry for thick cuts, crispy-skin targets, and flavor-forward outcomes.
| Factor | Wet brine | Dry brine |
|---|---|---|
| Speed | Faster (2-6hr typical for chicken breast) | Slower (12-24hr typical) |
| Moisture outcome | Retains more water (protein swells 10-15%) | Surface water drawn out then reabsorbed; net neutral |
| Crust / skin | Surface water kills browning unless rinsed + air-dried | Dry surface already achieved; superior crust |
| Flavor depth | Even but somewhat diluted | More concentrated; salt penetrates without water carrier |
| Over-salt risk | Higher (wet brine can saturate fast at high concentration) | Lower (self-limiting as water is drawn out) |
| Equipment | Needs container large enough to submerge protein | Just a wire rack in the fridge |
| Best for | Thin lean cuts · quick turnaround · added aromatics | Steaks · roasts · crispy skin · long planning windows |
Protein diffusion factors (why chicken ≠ beef)
Quick answer: salt diffuses ~2x faster through chicken breast than through beef roast because of muscle-fiber structure and fat content. Fatty cuts (pork belly, beef brisket) slow diffusion substantially because salt has to navigate around fat pockets. Fish is the opposite extreme — thin, open tissue, diffuses in minutes not hours.
| Protein | Diffusion factor (chicken breast = 1.0) | Typical brine time (25mm thick, 5% wet) |
|---|---|---|
| Fish fillet | 0.4 | ~10-20 minutes |
| Shrimp | 0.3 | ~15-30 minutes |
| Tofu (firm) | 0.5 | ~45 min-1hr |
| Chicken breast | 1.0 | ~1.5-2hr |
| Chicken thigh (bone-in) | 1.1 | ~2-3hr |
| Chicken whole / turkey | 1.2 | ~4-12hr (thickness-dependent) |
| Pork chop | 1.3 | ~2-4hr |
| Pork loin / tenderloin | 1.4 | ~3-6hr |
| Beef steak | 1.5 | ~3-5hr (wet) / 1-24hr dry-brine preferred |
| Beef roast | 1.8 | ~8-24hr (dry brine 1-3 days typical) |
| Pork belly / shoulder | 2.0 | ~12-48hr |
Salt concentration — the other lever
Quick answer: within the 3-10% wet-brine range, time scales roughly linearly with salt percentage. Doubling salt roughly halves required brine time. Below 3% salt, diffusion is too slow to be practical; above 10%, over-brine risk rises sharply and surface becomes osmotically stressed.
| Wet brine strength | Flavor profile | Brine time factor (25mm chicken breast) |
|---|---|---|
| 3% (mild) | Subtle seasoning; good for thin cuts | ~1.67x longer than 5% baseline |
| 5% (standard) | Baseline — most recipes | 1.0x baseline |
| 6-7% (strong) | Pronounced salt flavor; pull sooner | ~0.7-0.8x baseline |
| 8-10% (very strong) | Cure-adjacent; risks over-brine | ~0.5x baseline |
| >12% | Enter cure territory (bacon, gravlax) | Use separate cure-specific guidance |
Target salt uptake — what "done" actually means
Quick answer: the internal goal is 0.5-1.0% salt by protein weight. Below 0.5% you taste under-seasoned. Above 1% you taste over-seasoned. Above 2% you're in cure territory (different use-case; texture changes structurally). The wizard's goal presets map to different uptake targets: "even seasoning" aims 0.5%, "tenderize + moisture" aims 0.85%, "cure" aims 3%+.
Dry-brine specifics — salt by protein weight, not water
Quick answer: dry-brine uses 0.75-1.0% salt of the protein's weight (so 5g salt for a 500g chicken breast). Higher than that risks over-salt on the surface. The salt draws surface moisture out, dissolves in it, then gets drawn back in as a concentrated brine over 8-24 hours. End result: deeper seasoning + dry surface ready for high-heat cooking.
What this model does not capture
Fick's law is a first-order approximation. Real brining has complications: connective-tissue structure varies between cuts within the same animal type (rib-eye absorbs differently from sirloin though both beef-steak); sugar in a brine slows diffusion slightly via osmotic offset; aromatics (juniper, peppercorn, citrus peel) add flavor compounds that diffuse at different rates than salt (flavor rarely penetrates past the first 3-5mm regardless of brine duration); very cold protein (just out of freezer) diffuses ~30% slower than fridge-cold (plan extra time if starting from near-frozen).
Food-safety boundaries: always brine in fridge at ≤5°C (41°F). Room-temperature brining is unsafe beyond ~1 hour. For whole birds, plan brine-bag + ice bath if fridge space is limited. Always discard brine after use — do not re-use.
Sources and further reading
Harold McGee, On Food and Cooking 2nd ed. (Scribner, 2004) — Ch.3 meat chemistry, salt and water in muscle tissue. Cook's Illustrated, The Science of Good Cooking (America's Test Kitchen, 2012) — brine-specific chapters with tested timing tables. Nathan Myhrvold and Maxime Bilet, Modernist Cuisine Vol.3 (The Cooking Lab, 2011) — protein cookery, equilibrium brining, low-temperature applications. J. Kenji López-Alt, The Food Lab (W. W. Norton, 2015) — extensive dry-brine chapter with poultry and steak specifics. For cure-specific applications (bacon, gravlax, corned beef): Michael Ruhlman and Brian Polcyn, Charcuterie revised ed. (W. W. Norton, 2013).
Brining Calculator Tool v1 · canonical sources cited inline above · runs entirely client-side, no data transmitted