Magnesium Hydroxide Concentrate - 3 months old - Still Ok to use?

JHCCoffee

I three months or so ago made up some Magnesium Hydroxide concentrate (1.44 g magnesium hydroxide in 500 ml RO water) with the intent of using it in a water recipe. I never got around to using it, as I have been simply using sodium bicarbonate water.

However I have been following the thread on adding minerals to espresso after brewing, to experiment with taste. So I might use this concentrate in a water recipe, that I would then add to my espresso.

Assuming that there has been no evaporation (which I can then correct) and that the magnesium hydroxide has not settled out, is it safe to use this concentrate? It has been stored in a sealed bottle but I am betting that their is air in the bottle. I would think it is safe and that the resultant water will taste good (not off or stale) but I thought I would ask.

Fyi, based upon @Rob1 s recipe, I will use 15 ml of this concentrate in 2,980 ml of zero water. I will then add 13.7 ml of my sodium bicarbonate concentrate, which is made up of 8g of baking soda per 1000 ml of RO water. I think I got this recipe right?

Just being lazy, as I will otherwise need to use my soda stream to make up a new batch of concentrate.

CoyoteOldMan

JHCCoffee A bit late… but my thoughts about safety are that after 3 months I’d replace it. It may not look, smell or taste funny, but a lot of poisonous stuff doesn’t.

I also suspect that adding tiny amount of minerals after the brewing process will do exactly nothing to the taste. A grain of table salt weighs about 5 micrograms; if you added one ml of your concentrated Mg(OH)₂ solution to your brewed coffee you’d be adding about 1200 micrograms of Mg. I added the equivalent amount of magnesium via magnesium sulphate (~10 mg) to a cup of coffee, and I could not taste any difference… including the significant bitterness of the sulphate addition!

Rob1

Is this a hazy mixture of magnesium hydroxide in water? The last comment about the soda stream suggests not.

I can’t comment on the safety of it at all.

What is it you’re trying to do? You mention adding water to espresso but then talk about diluting the concentrate in close to 3 litres of water.

JHCCoffee

Rob1 What is it you’re trying to do? You mention adding water to espresso but then talk about diluting the concentrate in close to 3 litres of water.

I’ve been following a thread here at CoffeeTime about adding minerals to an espresso shot to test taste impacts. I’m not sure how to go about this. I’m thinking of testing the hydroxide water recipe in this manner. The question then becomes: if I add fully diluted hydroxide water, then the espresso will taste, well, diluted. So I suppose I should add more concentrated hydroxide water. If so, how concentrated?

Alternatively I could use the fully diluted water to make an Americano?

Or maybe this simply won’t work.

JHCCoffee

Thanks CoyoteOldMan
Will throw out my old water and make a new batch as and when I’m ready to test the taste impacts of that water recipe in the actual brew process.

Thanks as well for the taste test. We’ll pass on that idea.

I’m going to switch back to the “Adding Minerals to Coffee” thread and chat about making a calcium concentrate and adding it to espresso after the brew the brew process.

Rob1

You need to calculate what the concentrate should be based on the beverage mass.

If you’ve added magnesium hydroxide to carbonated water and the water is not cloudy you have a solution of magnesium bicarbonate, not magnesium hydroxide.

edit: edited to prevent confusion. You really need to weigh very small amounts of additives precisely if you’re making small amounts of the concentrates. e.g the amount of Sodium bicarb to make 100ml of a solution that adds 40mg/l alkalinity when 1ml is added to 36ml is 0.044g If you up the batch size to 1 litre you’re still going to need to accurately weigh 0.44g.

Rob1

[unknown]

This is wrong. But anyway for Magnesium Hydroxide 0.064g in 100ml for the concentrate if you want to add 1ml to 36ml and get hardness of 30mg/l. For the sake of accuracy I’d prefer to be adding grams so would be looking at dropper bottles that add 0.5ml per drop and would make 1 litre of the concentrate which would require 1.276092506g dissolved in carbonated water….obviously you’re just aiming for1.27 or 1.28g. Bear in mind you’re also adding alkalinity in equal amounts so a Magnesium bicarbonate concentrate for this purpose is probably not ideal unless you just happen to want to add both 30mg/l hardness and alkalinity. Best looks for chloride or sulfate salts really and have a much easier time with it too.