Distilled Water vs Reverse Osmisis Water

[mshergold]

Hi. Not exactly a post about brewing liquor I know, but water-related nonetheless (though please move if necessary!). We've bought an acid test kit as We need to harvest and crush our grapes tomorrow. However, on reading the instructions after it arrived yesterday, I've discovered that We need distilled water. Which nowhere seems to stock (except scented for ironing). Chemists no longer seen to stock it and Halfords 'distilled' water is actually de-ionised.

So my girlfriend called a garden centre which sells fish. "Yes. We sell it" they said. "£1.79 for 10 litres". We didn't want 10 litres, but it was cheap and if turns out it's RO. We don't have the time to go chasing across the country to find some , so can anyone tell us if we can use RO to replace distilled, or any anywhere guarantee to distilled water and will be open tomorrow afternoon somewhere between Wembley and Dagenham?

Thanks!

[Wonkydonkey]

You did not really say what you want it for, as far as I can read/see.

Distilled is water turned into steam, leaving all the other stuff behind, then turned back into water via condensation.

RO water is water that has been forced throu a membrane that mostly only lets water through, a bit of other stuff finds its way through.

So to give you an idea, I have tap water which is hard 230-odd caco3 and all the other stuff in it.
So if I test my tap water with a TDS meter, I get a reading of 260-ish total dissolved solids
And if I test the RO water I get a reading of 5. So my RO unit (newish) takes out 99.9% -Give or take 0.05% of those solids

So for some things RO is fine,

I hope this helps, as it has taken me a lot longer typing it, rather than if I said it

Edit, acid test kit, is this what your using it for? How will you use it.

[mshergold]

Hi Wonkydonkey. This is the kit. It's to test the acid content of crushed grapes. This is the kit:

https://www.brew2bottle.co.uk/wine-and- ... t-kit.html

[Wonkydonkey]

Ok, after a long night out, I got in at 3am. I've had breakfast/lunch and feel better.

So after looking at the link you gave and a quick search on Google, I came across a forum. Which gave a bit of info, cos I could not read the instructions which are in the box.

Red wine it's hard to see the colour change, so you use distilled water to lighten up the colour in the red wine to see the colour change a bit better.
So the wine has the acid, you add the indicator/colour change then drip by drip you add the NaOH, once the naoh has used up the acid in the wine the colour changes pink.
Your problem is adding water to dilute the wine, the acid will react with chalk in the water. Ie give you a diffent value.
Tbh. I don't think it will make much difference. But what ever your reading/acid value is. It will be a little more as the chalk has used a bit of the acid up already.
The only thing I would do is ask the fish shop what is the TDS of the water they sold you and how often they check the TDS .
The TDS is what really tells you when to change the filters and membrane. And as I said before my filters and membrane are almost new. Had about 1000lts of water gone throu it.
So the shop may have older membranes/filters so could be letting more through and have a higher TDS reading. Which you may need to take into account. Also the more you dilute the sample the more chalk your adding.
But All this could be irrelevant, if your testing white grape/wine.

Anyway I hope this helps you.
But next time you may want to plan it a bit better. Eg. I have an air still, which I got for £3 at a car boot sale. So I can make distilled water. maybe you know someone with an air still

[Aleman]

Halfords - Deionised water, same from our morrisions