When Your Process Cannot Tolerate Water

Hagalah is done with boiling water. For a great many plants that is unremarkable. For some it is a direct conflict with the process, and the conflict is real rather than an excuse.

A few drops of water will ruin a large vessel of chocolate. The same is true, in their own ways, of margarine, edible oil and glycerine lines. And the risk is not only during the kashering: if you flood a system with water, the concern is that not all of it drains, and the residue spoils production afterwards.

So the question that reaches us is a fair one: can we kasher with something our process can actually tolerate?

Why water, specifically

It helps to know the reason before arguing about the exception. Other liquids are held to behave the opposite way from water — their nature is to be absorbed into the vessel rather than to draw out what is absorbed in it. A kashering medium has to pull; these push.

The Rema does record that after the fact, hagalah in any liquid works — there are authorities who hold other liquids expel like water, and one may rely on them bedieved. That bedieved allowance is the foundation of every argument made here.

What has been tried

Two things are worth noticing about that list. The permissive rulings are narrow and case-bound — each rests on a particular feature of that plant, not on a general principle that water can be substituted. And the reasoning that gets you there is shaas hadchak: the risk of ruin and loss being treated as pressing circumstances, on the rule that pressing circumstances can be treated like after-the-fact.

The chocolate case, worked through

This one repays following, because the industry had already solved it to its own satisfaction and the solution did not hold.

The practice in a number of factories had been to make pareve chocolate in the same equipment that had run dairy chocolate hot, kashering in between. Water was impossible for the reasons above, so they kashered with other liquids, relying on the bedieved allowance and treating the loss risk as shaas hadchak.

Then the obvious refinement: other liquids carry the same ruin risk that water does — a few drops of any foreign liquid spoils a vessel of chocolate just as surely. So the practice moved to kashering with cocoa butter, which is what the chocolate is made from and therefore cannot spoil it.

It is a genuinely clever answer. It was still rejected: the conclusion reached was not to rely on that form of hagalah for making pareve chocolate in factories.

The lesson generalises. Finding a medium that does not damage your product solves the engineering objection, and the engineering objection was never the halachic one.

Where this leaves a plant

The summary position is that one should not be lenient about kashering food-production machinery with liquids other than water, nor by sacrificing a first production run — but that each machine is judged on its own facts.

That last clause is not a formality. The permissive rulings above exist, and they exist because a specific plant's specific constraints were put in front of a posek who examined them. What does not work is deciding in-house that your line is a shaas hadchak and proceeding.

So if water is genuinely impossible on your process, the productive move is to bring it forward as an engineering fact with detail — what the medium is, what the temperatures are, what happens if water enters, what drainage exists — early enough that the answer can shape the schedule. Some of those questions have been answered permissively before.

The unproductive move is to treat the water requirement as negotiable in principle. It is not, and the cases where it bent were narrower than they look.

See also kashering a food plant and shared equipment. Your own process is a question for your certifying rav.