using deionised water

[tim99]

Hi to all , as i have now done 2ag brew i thought i might look at water treatment . Armed with my litmus papers i checked my tap water (6.0 unboiled) and as i can make deionised water(using carbon filter /granule/ro membrain) i checked this. It came out at (4.4)
now a very rare bright idea came to me why not mix both to get 5.2 which i did . It came out about 5.3 50/50 mix

i have looked at my local water report online but years old (scary data overload)and thought doing this might be more accurate?

my concern my deionised water. The second filter is backflushed with salt to attach to the ions in the water so the ro membrain can filter them out (does,nt taste ) the tds is reading 0002ppm. The unit makes about 800 litres in four hours

any comments welcome or other ideas

[EoinMag]

Hi to all , as i have now done 2ag brew i thought i might look at water treatment . Armed with my litmus papers i checked my tap water (6.0 unboiled) and as i can make deionised water(using carbon filter /granule/ro membrain) i checked this. It came out at (4.4)
now a very rare bright idea came to me why not mix both to get 5.2 which i did . It came out about 5.3 50/50 mix

i have looked at my local water report online but years old (scary data overload)and thought doing this might be more accurate?

my concern my deionised water. The second filter is backflushed with salt to attach to the ions in the water so the ro membrain can filter them out (does,nt taste ) the tds is reading 0002ppm. The unit makes about 800 litres in four hours

any comments welcome or other ideas

If you use deionised water you will need to know what ions it now contains, my thoughts are that it replaces the hardness with sodium which does not express as hardness afaik, so the water is high in sodium but low in Calcium, so not very healthy for a start. Then you need to actually add all the salts that you do need to make up the profile that you want.

It's not as simple as the water that goes into the mash measuring 5.2 premash, because the interaction of the grains will throw that again and it won't stay at 5.2 when mashing. Water chemistry in brewing is about laying down the basis that will cause the mash to hit 5.2 (or as near as possible) when the grains are added.
It becomes a harder job than just adding CRS and DLS to the liquor to get to some known values.

I'm sure there are others who can help you on this who do use RO water, but it doesn't quite give you a blank canvas to work with and means you are building your water profile effectively from scratch, but with a known lot of nasty sodium in there in place of the hard Calcium.

That's my take on it anyway.

[tim99]

many thanks ,its just me thinking about water while reading as much as i can chemistry wise
as far as i can gather about my ro unit the salt binds(one filter is flushed with 500gms of salt/ fresh water for 10min before filling) to the ions to make them unable to filter through the ro membrain 20% goes down the drain 80% is forced through the membrain which takes the water down to 25ppm then a final filter takes out the final ions to 5ppm
by mixing with fresh tap water i thought it might get me somewhere near 5.2 before mashing

[EoinMag]

many thanks ,its just me thinking about water while reading as much as i can chemistry wise
as far as i can gather about my ro unit the salt binds(one filter is flushed with 500gms of salt/ fresh water for 10min before filling) to the ions to make them unable to filter through the ro membrain 20% goes down the drain 80% is forced through the membrain which takes the water down to 25ppm then a final filter takes out the final ions to 5ppm
by mixing with fresh tap water i thought it might get me somewhere near 5.2 before mashing

You can use RO water, it is possible, but you just need to do some more reading on how to get there and then balance the minerals in the water, but my understanding is that sodium levels become a dietary concern.

I think you lose 80% down the plughole with RO, not the other way around, I remember it being horribly inefficient which is why I didn't consider it.

From wikipedia:
Household reverse osmosis units use a lot of water because they have low back pressure. As a result, they recover only 5 to 15 percent of the water entering the system. The remainder is discharged as waste water.

http://en.wikipedia.org/wiki/Reverse_osmosis

[tim99]

it,s an industrial unit which holds 800litres i made a mistake it only dumps 8% dependant on water temp pressure max of 14%

have read more by john palmer looks possible to mix 50/50 with tap water