Vacuum Infusion of Porous Ingredients — Mushrooms and Celery

Ferran Adrià's kitchen at elBulli systematized vacuum compression of fruits and vegetables in the late 1990s as part of a broader investigation into texture manipulation through controlled atmosphere. The technique moved into savory applications — particularly with fungi and aromatic vegetables — as chamber vacuum sealers became standard restaurant equipment in the 2000s.

Every mushroom and every stalk of celery is a sponge. Cellular structure is riddled with gas-filled intercellular spaces — in cremini that's roughly 10–15% of total volume by air; in celery it's even higher given the aerenchyma tissue that runs through the ribs. Vacuum infusion exploits that air. You place the ingredient in a liquid — a dashi, a mushroom consommé, a seasoned brine, a vinaigrette — and drop the chamber pressure, typically to 50–99 mbar absolute. At that pressure, dissolved and trapped gases inside the tissue volatilize and escape into the headspace. When you vent back to atmosphere quickly, the pressure differential drives the surrounding liquid violently into the vacated intercellular spaces. The result is not marination — marination is diffusion and takes hours or days. This is mechanical displacement: liquid occupies space that was air, immediately. For mushrooms, the payoff is dramatic. A 15-minute cycle in a concentrated mushroom dashi at 90 mbar will load a raw button mushroom with enough liquid that slicing it releases broth the way a braised product would, but the cell walls are still structurally intact — no heat damage, no shrinkage, no loss of the mushroom's own aromatic volatiles. For celery, you get translucency and a completely different textural register: the crunch remains, but the fibrous chew disappears because the air pockets that gave celery its brittle snap are now liquid-filled. Celery infused with a Bloody Mary mix, or a tarragon vinegar, or even a chicken fat emulsion, eats like a juicy, tender vegetable rather than raw roughage. The fluid you choose is everything. Thin liquids penetrate faster and more completely than viscous ones; anything above roughly 5 cP starts slowing infusion measurably, per Myhrvold et al. Run multiple cycles — vent, re-seal, pump down again — rather than one long hold; each cycle displaces another fraction of residual gas. Temperature matters too: cold liquid has higher surface tension, which can slightly resist capillary entry. Room-temperature liquid at initial pump-down, then chill post-infusion, is the standard professional sequence.

Mushrooms carry glutamic acid and 5'-nucleotides, particularly guanosine monophosphate, concentrated in the cell sap. Vacuum infusion preserves these intact — no Maillard, no thermal denaturation — so the raw umami compounds stay soluble and bioavailable. When you load additional glutamate-rich dashi into the intercellular spaces, you're stacking umami synergistically: the mushroom's own GMP amplifies the dashi's glutamate through the nucleotide–amino acid synergy documented in McGee (On Food and Cooking, 2004, p. 290). Celery's dominant volatiles — phthalides, specifically 3-n-butylphthalide — are largely fat-soluble and concentrated in the ribs. Infusing with any fat-containing liquid (a chicken fat vinaigrette, an olive oil emulsion) allows those aromatics to leach slightly into the infusion liquid even as new flavor compounds enter the tissue. The net effect on the palate is a vegetable that tastes simultaneously of itself and of its infusion medium, without either drowning the other.