I thought she meant that the sweeteners themselves become bitter if they are permitted to age, whilst being free from admixture with other substances.
And these:
(a bunch of portable gas cylinders, mostly argon, and CO2 (separately, not as a mixture) plus a new regulator as my other one, now reserved, after a thorough scrubbing clean had been corroded a fair bit by exposure to something like a mist, or fine spray, plus the occasional direct blast, of a mixture of sodium hydroxide and potassium hydroxide (NaOH, KOH, caustic soda and caustic potash respectively, aka lye and potash lye) in the form of their being put in a carbon crucible, and heated in a bath of molten lead until they fuse, drive off the water to give an anhydrous liquid melt, taken to about 500-600 degrees 'C to drive off residual H2O (caustic potash is particularly difficult to get truly anhydrous, apparently, commercial 'anhydrous' KOH contains usually up to 20% water by weight, and it loses that water with extreme difficulty, to the extent it is usually dried with potassium or possibly with sodium metal, and the residual metal distilled off under high vacuum, when its needed to be absolutely, truly anhydrous.
In this case it was taken to 500-600 degrees in a metal bath filled mostly with lead, but some tin in there since lead is nasty and the less fumes the better. Without a gas mask that bath makes my teeth feel metallic if I'm using lead as the thermal transfer liquid. Going to invest in a big lump of bismuth, since it has a low MP and high boiling point, as well as very low toxicity compared to pretty much any other heavy metal, so will be ideal for such applications. Then l'd let the lead-tin mixture cool to a little over 200 degrees 'C so it solidified and with pliers holding the crucible down (its light in weight, so it tries to float on the molten lead, so the trick to keep it in place is to ram it down with pliers and hold it there until the lead solidifies, thus locking the crucible in place in a lump of solidified, but still very hot lead)
Then turned the heat to 200 'C, or rather just over it, so as to reach the melting point of the eutectic mixture (a eutectic is a mixture of salts that depresses the melting point past either salt on their own. Caustic soda for example, and caustic potash melt at 318 'C and 360 'C respectively, but a mixture of both sodium and potassium hydroxides melts at just 200 'C. This has the advantage for the use in question at the time, namely my using the heat bath and crucibles to perform electrolysis of the molten salt mixture liberating sodium and, since the eutectic was used, potassium, which even at room temperature is a liquid metal alloy, known as NaK. Its extremely reactive, and indeed much more so than potassium and vastly more reactive than sodium. Where during electrolysis in open air, blobs of sodium form and are likely to explode the moment they hit air when molten, with NaK, despite its reaction with water being violently explosive and igniting very rapidly, spontaneously in air, whilst with sodium or potassium, or lithium you can take it out of its container, especially if in oil rather than dry and sealed under either vacuum or inert gas, and taking a knife, slice off a chunk of either sodium or potassium (or lithium. Not sure about rubidium, I've never actually handled any rubidium or owned any. Its very expensive, although I'd like to get some rubidium chloride or hydroxide and perform electrolysis in a vacuum chamber or sealed chamber with a one-way valve allowing exit only,purged repeatedly with inert gas, then, in the same chamber, purge a borosilicate glass ampoule and quickly pipette or inject the molten rubidium into the amp, then flame-seal it with a plasma torch running on something like an argon or nitrogen flow to create the plasma (since in the anoxic environment vital for handling and especially electrolysis of molten rubidium salts, and handling molten rubidium metal [its an alkali metal, one step below potassium, if you take below to mean looking down from lithium at the top and francium at the bottom, and is more reactive than potassium, but like caesium is very, very reactive and more so than potassium and as such would be very violently reactive towards air or atmospheric water vapor content when molten, at the temperatures requisite to melt the salts in order to pass the electric current through to free the Rb metal]
As for NaK alloy, its as I said more reactive than either sodium or potassium, when the two combine as an alloy. Also liquid at room temperature so it can spread out, allowing the entire mass to react at once and in my experience with it, when the NaK is being created, rather than handling already existing NaK, it is so highly reactive that in fact it doesn't explode during electrolysis if performed in open air (you won't actually isolate any, its far too reactive to isolate in an open air electrolysis. Small amounts of sodium or potassium can be, although with difficulty. It is possible to perform an electrolysis and obtain enough of the metal, given enough time, effort and quick reactions as well as full face shield etc and long gloves, since you really do NOT want to be exposed to molten caustics, its one thing as a liquid solution, washed off, but quite another beast entirely at several hundred degrees as a molten salt. You can do it though and obtain beads of Na, K etc and store them in oil or under vacuum, or inert gas with oxygen absorbing dessicant mixtures (I have my lithium stored dry, with no oil, in a marmalade jar, sans marmalade of course, purged thoroughly with argon, the threads wrapped in teflon tape and in a bag, with only a small opening in the thick plastic, where some lithium has been taken out and used. Outside of the bag containing the squares of lithium metal, I've poured a mixture of finely powdered, freshly roasted dry anhydrous calcium chloride, mixed intimately with 300-400 mesh magnesium dust (about 40 micron particle size IIRC, a very, very fine, fine fine dust of magnesium metal, the CaCl2 being to absorb any water vapor not displaced by the dry argon used to purge the jar, whilst the magnesium dust, being much cheaper than lithium, and easily available, serves as a sacrificial fuel, being oxidized by any traces of oxygen present.
And in fact there is less corrosion in it than there is on a couple of the surfaces of my brick of sodium metal, which is oiled in something like thick paraffin oil or vaseline, and vacuum-sealed in a thick inner plastic liner which was then heat-sealed, and placed within a second, hermetically sealed thick walled plastic bag which has been purged with some sort of inert gas.
