Simmer the shallots in the vinegar and reduce by half.
Squeeze out the liquid and reserve.
Add lemon juice
And water all in a sous vide bag.
Cook in combi at 167F (75C) for 30 minutes on steam mode.
Add contents to your whipping siphon.
Load with two charges of nitrous oxide.
Shake and dispense. Hold at 149F (65C) until needed.