Corn Relish

This is a home-canning recipe, and the instruction that matters most — how the jars are sealed and processed — is missing entirely. The notes below explain why it should not be followed as printed.

• "Can and cover" is not a processThere is no jar preparation, no headspace, no boiling-water bath and no processing time. Filling jars with hot relish and covering them relies on nothing but residual heat for a seal, which is not a reliable method for shelf-stable preserves.
• Corn is a low-acid vegetableSweet corn and celery are well above pH 4.6, and safety here depends entirely on the vinegar bringing the whole mass down and holding it there. With the corn quantity absent altogether, the finished acidity is unknown and cannot be estimated.
• The specific riskUnprocessed, imperfectly acidified low-acid vegetables sealed in jars at room temperature are the classic setting for Clostridium botulinum. The toxin leaves no smell or off-taste, so a spoiled jar cannot be identified by inspection.
• Vinegar strength is unstatedThe recipe names neither the type nor the strength of the vinegar, and historic vinegars varied in acetic acid content rather than being standardised at the 5 per cent sold today. Modern tested relish recipes specify the strength for exactly this reason.
• The earthenware panVinegar and turmeric are both aggressive, and an unreactive vessel such as glazed earthenware or enamel avoids the metallic taint of tinned copper or bare iron. Old glazes can carry lead; stainless steel is the modern equivalent of what the instruction intends.
• Twenty minutes of cookingThat is a long simmer for cut corn and chopped celery, and both will be soft rather than crisp. But the cooking time is not what makes this version unusable.
• If you want corn relishUse a current tested recipe from a reputable preserving guide, which will give you the vegetable weights, the vinegar strength and a processing time for your jar size and altitude.