Nitrite Meat-Curing Reaction-Diffusion Simulator

Curing Brine

Surface nitrite dose 150 ppm

pH 5.5

Temperature 4 °C

Simulation speed 2 hr/s

Live Readouts

Elapsed time

0.0 hr

Cure depth

0.0 mm

Microbial kill

0 %

Avg. residual NO2-

0 ppm

Raw myoglobin (uncured)

Nitrosylmyoglobin (cured, pink)

Viable bacterial spores

Inhibited spores

How it works

Nitrite (NO2-) from a curing brine diffuses into the meat and undergoes acid-catalyzed disproportionation, generating nitric oxide, which drives both the cured colour and the antimicrobial effect:

Fick diffusion + first-order decay (per voxel):
  dC/dt = D grad^2 C  -  k_r C

Acid-catalyzed nitrous-acid disproportionation:
  3 HNO2 -> HNO3 + 2 NO + H2O     (k_r rises as pH falls)

Pigment formation (NO binds deoxymyoglobin):
  Mb + NO -> MbNO   (nitrosylmyoglobin, the pink cured colour)
  pink(x) = 1 - exp( -dose(x) / D_pink ),  dose = integral of k_r C dt

Antimicrobial inhibition (NO attacks Fe-S clusters /
thiol enzymes bacteria need for spore germination):
  viability(x) = exp( -dose(x) / D_kill ),   D_kill > D_pink

Surface nitrite dose — the fixed NO2- concentration held at the top face of the slab, like meat sitting in a curing brine (Dirichlet boundary condition).
pH — lower pH means more nitrite sits as protonated HNO2, which disproportionates faster into NO; curing brines are typically pH 5-6.
Temperature — raises both the diffusion coefficient D and the reaction rate k_r (Q10 ≈ 2 for each), so warmer curing is faster but less controlled.
D_kill > D_pink in the model on purpose: real cured meat reliably turns pink well before it has accumulated enough NO exposure to reliably suppress Clostridium botulinum spores — colour is not proof of safety, which is exactly why regulated minimum nitrite doses and cure times exist.

The grid uses an explicit finite-difference stencil with a stability-limited timestep (dt ≤ dx²/6D in 3D) sub-stepped every frame, so raising temperature or simulation speed automatically increases the number of physics substeps per rendered frame.

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