My high-tech curing stash vision

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Notorious Lyear
Jan 14, 2021
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tl;dr: An airtight cabinet to cure and store bar soaps in, filled with dry nitrogen at about body temperature.

Brain dump of how such a dream rack might be like:
  • Air-tight, with closed-cycle air conditioning/agitation
  • Dehumidifier: withdraws water from the air inside, keeps the humidity at a constant (low) level optimal for quick diffusion of water evaporating from soap bars. The air movement could be directed in a counter-current way: older soaps get the driest air, and young soaps are placed “behind” them to not be shock-dried.
  • Not filled with air, but (reasonably) pure nitrogen. i. e. much less oxygen, carbon dioxide and water vapour than regular air. This means that one could discount the curing time from shelf life of oxidation-sensitive ingredients like poly-unsaturated fats or plant-based colours. No O₂ = less ROE/BHT. No water = no glycerin rivers. No CO₂ = no soda ash!
  • Air filtering: extract excess moisture, CO₂, scents etc. from the steady air stream inside the stash (cold trap?).
  • Temperature: Room temperature for regular storage is one option. But since we're dreaming, I dream of slightly elevated temperature: more rapid water diffusion (drying; note that the soap cannot dry out if the air humidity is kept at a level that is a sane compromise between drying speed and residual moisture in the soaps), reduced likeliness to develop stearic spots.
  • Say, we keep the temperature at 37°C: the soap cures at body temperature. An, if you want so, esoteric sounding side effect is that the soap might “feel at home in your hands”. Of course soap is not self-conscious and cannot “feel”, but who knows? I can well imagine that a soap molecule crystallisation at elevated temperature would impact mechanics, solubility and skin feel of soap; it will have some effect on soap recipes in any case (and be it just that you can circumvent time-proven INS/iodine limits).
  • A separate section could be held at temperatures between classic CP and CPOP close to 100% relative humidity. This avoids drying of any kind, e. g. for CP liquid soap paste. Other zones at other humidity and temperatures are imaginable for specialty soaps. Or even a vacuum chamber, where reduced air pressure greatly accelerates the evaporation of volatiles (water).
(Some) open questions:
  • How to bring soaps into the cabinet, and out again? Gloveboxes and air locks exist, but are super cumbersome to operate. My craziest idea was to divert a magnetic tape archive robot for this task. A welcome upside of having to “program” access to your stash is that your computer does automatic bookkeeping over current stock, curing times, etc., and cannot confuse batches.
  • Packaging. Soaps would be delivered to a shop/customer. Either you start counting days from when you take them out of their nitrogen prison, or you have air-tight packaging. In any case, at the very latest when the customer opens the packaging, the clock will start ticking. Something to accustom customers to.
  • Marketing/advertisement/customer communication. How much and in which tenor to exploit this special curing technique?
  • Impact on curing time. I can well imagine that, with increased molecular mobility, restructuring takes place faster than at room temperature. It might be a way to speed up curing, or it might not be; in any case, the window between not-use-before and not-use-after dates is much wider than with plein-air soaps.
  • In recipes with tight lye discount limits, usually CO₂ might help neutralise minimal lye excess and make soap milder over time. It might be a good idea to divide my sci-fi soap stash into a “saponification” unit (pure, very dry N₂) and a “curing” zone (minor moisture and CO₂ additions).
  • And finally the most relevant question for notorious low-INS/high-iodine soapers like me: How far can you push the limits of poly-unsaturated oils? A more aggressively drying atmosphere might help you get a castile-like structure from high-linoleic oils, or just most of your palmitic/stearic additions. Without oxygen (and with proper chelators added), rancidity/DOS should be a lot less an issue, at least during manufacturing/curing (see packaging question above).
Lesion learned (pun intended): there is no limit to over-engineering!
there is no limit to over-engineering!
You'd get on well with my husband! 🤣

I've been considering some of the same problems, although I don't plan to take it to quite the same extreme ;)

We've almost finished converting an outbuilding into a craft room and I plan on having some kind of climate controlled cabinet in there for soap curing purposes but also for brewing. Plenty of food for thought in your post above!
You'd get on well with my husband! 🤣
Don't act as if you were free of that!

We've almost finished converting an outbuilding into a craft room and I plan on having some kind of climate controlled cabinet in there for soap curing purposes but also for brewing.
Great idea! My thoughts were purely that: thoughts, fantasies, dreams. But you two are already several steps further. Brewing is something that wins from temperature control too (not sure if the temperature range is ideal for soap curing, though). But be sure the fermentation CO₂ doesn't interfere with the soaps (soda ash!!!!), neither the other way round: the beer/wine/cider/sauerkraut/water kefir/sourdough/miso/tempeh/natto/filmjölk/cheese better don't end up smelling like your expensive FOs. 🤣