RO water

[RobinB]

What is the profile of RO water ??

 

[strange-steve]

It depends on the profile of the water going in, but an RO filter should reduce all ions to <5% of their pre-filter concentration. So in practice, unless the supply water is extremely hard it probably wouldn't make much difference to assume zero for all ions.

 

[scomet]

depends on how good your RO membrane is, some give RO at 1ppm which is a clean slate, others give 10 to 25ppm. I have heard RO sales peps saying "our membranes are designed to give 25ppm minerals" BS on that they're just rubbish Chinese copies, ppm metres are cheap. Dow Filmtech make the best membranes imho - Cheers

 

[RobinB]

If I use RO water ... what do I add to make my target profile?.. And where is this information ?

 

[scomet]

Water Calculator
https://www.thehomebrewforum.co.uk/pages/water-calculator/

From this forum on front page, lots of others on line, Brun water is great but a bit complex but the subject is!!

Good luck

 

[scomet]

In saying this if you're in the UK your water will be pretty good, If you've only just started brewing water should be the last thing on your list to improve your beer. Where I am it is full of chlorine and chloramine RO made a huge difference to my beer

 

[steveinUS]

My tap water has chlorine and is very high (~400 ppm) in dissolved solids. The output from my RO filter has zero chlorine and <10 TDS. Depending on the beer I am brewing, I blend my charcoal-filtered tap water with half (for dark beers) to two-thirds (for lighter beers) RO water.

For extract brewers, best practices are to use only distilled or RO water because malt extract already contains all of the mineral content from the water it was made with.