Posted by Meggings (here)
Bob, thank you for starting this thread on magnesium bicarbonate.
I researched and made this many years ago, but when my kids arrived to live under my roof, as the phrase goes "all hell broke loose" and I lost my seltzer water bottles, Milk of Magnesia, and even the made-up bottle I had in the frig.
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Hi Meggins - it's certainly an interesting form of Magnesium.
This is what the bottle looks like after shaking, with having about 2 ounces of the really CHILLED seltzer removed, BEFORE adding in the 3 table spoon fulls of the Milk of Magnesia (Magnesium Hydroxide initials M.O.M.).
I put the chilled bottle in the sink once again, in-case of any spillage just in case.
As soon as I added the M.O.M. the mixture started bubbling, and I rapidly put the lid back on the bottle, and closed it tightly.
I picked up the bottle and started shaking it.. As I was shaking it it sure felt like it was getting colder - maybe the reaction absorbs heat from the environment?
The bottle at first was quite pressurized, but as I continued to shake it, (total of about 3 minutes of shaking), I noticed that it was starting to cave in already ! Maybe the extra headspace at the top of the bottle allowed for better mixing of the CO2 with the M.O.M. I continued shaking and it finally reached the picture you see here:
At this point the bottle was caved in, but I did NOT release the cap, but put it in the fridge once again, to let it set for an hour. At the end of the hour it should be pretty much clear. At that point opening the cap to let the air in should be OK. I'm preferring to store it refrigerated although, it has no organic material in it, it should last OK.
Personally, I prefer to make a new bottle every time the older bottle has about 2 ounces left in it.
==Update==
Taking out the two ounces of seltzer at first to 'make room' appears to not be the best idea as the full bottle's worth of CO2 apparently is needed to get all the hydroxide converted to bicarbonate.
So after the 2nd hour, opening the bottle, then adding 2 ounces of fresh seltzer was done. Shaking the bottle, and again it started to cave in. I assume then what that means is the CO2 is being absorbed once again.. I'll see what it is like in a couple hours. They keys appear to be chilled bottle of seltzer before opening, and to not jostle, carefully and slowly open the cap the first time and rapidly add the M.O.M., quickly close the cap.
===Update 2===
TESTING this BATCH: The bicarb taste was there, but just not as strong as it was with bottle 2. So after I had poured out the 1 ounce from this made up batch, I added in another ounce of fresh seltzer to this 3rd bottle to bring up the CO2 level.. And shook it and immediately it started to cave in, meaning the CO2 was being consumed rapidly..
What this tells me is this bicarbonate conversion process really could use as much CO2 as possible and keep the pressure up and the mixture COLD.
I'll try this extra CO2 from the one ounce replacement for what I took out this morning, and test later today to see what it tastes like. The bicarbonate taste is very recognizable.
I'm beginning to feel the initial recipe of "one FULL litre chilled seltzer" and 3 tablespoons full of M.O.M. and allow for some bubbling over is OK..
Probably the 3 tablespoon fulls of the mixing being added to the bottle when it is in the sink takes into account some MOM source loss. It will bubble over and some MOM will be spilled into the sink.
OBSERVATION: If there is too much milky color sitting on the bottom of the bottle after 1 hour of when it caves in, then possibly there was never enough CO2 in the starting bottle for the amount of MOM added..
Maybe decreasing the initial amount added to the bottle to 2 - 2.5 tablespoon fulls would be better. Keeping the CO2 UP seems to be key to the best conversion. It should only have a slight amount of visible sediment on the bottom of the bottle after an hour of sitting after it caved in.
===Update 3===
Adding more seltzer, one more ounce after removing one ounce of the CONCENTRATE batch, did not cause the bottle to cave in this time. Tasting the batch definitely had the "bicarbonate" (sorta like a fizzy-type of taste instead of strange 'sweet').. And there was absolutely NO residue left.. That confirms that this process requires a LOT of CO2.. And if residue has appeared, the mixture has not reacted completely (needing more seltzer to be added).
It looks like a 'work in progress' to tailor the brand of seltzer (CO2 content) and the MOM particular brand (the additives for instance added can change the recipe slightly it seems).
The right tasting mixture appears to be quite delightful in perceived affects. A mixture which is not completely reacted (converted to bicarbonate) appears to work, partially but the effects are less dramatic. Fresh mixtures so far seem to be best.. (Not enough data on this yet)..