[copachino]

hi all, i have a not so good water supply, so im looking for a RO system for mead and breweing beer, i know that for beer its not a big deal since you bild the most, but for mead?, im asking this because the seller just told me that the RO system they have a 5 filter system doesnt make the water for suitable for drink, but im not sure if he its mistaking something, or maybe the RO doesnt remove any bacteria or other bad stuff in the water.

[mabrungard]

OK, your RO system seller is trying to scare you and probably wants to sell you a UV sterilizer unit. 

The RO process does remove ALL bacteria and virus from the treated water (assuming the membrane is intact).  But this does not mean that you can't have organisms grow downstream of the membrane.  All the disinfectant has been stripped from the treated water and things can grow.  But it is incredibly unlikely that anything life-threatening would grow in that water.  Assuming that you are reasonably sanitary when you assembly and operate your RO system, you won't have anything to worry about with respect to drinking that water.

Since you're talking about mead, that introduces the possibility that you're not heating that RO water enough to kill must-spoiling organisms.  For that reason, you could have a reason to be concerned with the water sterility.  It would be wise to pre-boil that water briefly to help sterilize and as its cooling, you can add the honey to get it to dissolve faster. 

Do understand that if you're using RO water for mead, it is imperative that you add certain salts to the water to aid in the fermentation.  You do have to add between 5 and 10 ppm magnesium to the water for yeast health and you should probably add at least 40 to 50 ppm calcium too.  Its your choice as to using a chloride or sulfate form of those salts.  I'd say that keeping the chloride and sulfate content even, would be wise.

[copachino]

thank you for your reply,

since this little spoil beasts can grow on the filter lines, i believe then i more simple solution its to boild but setting all stuff to boil then cooling its quite demanding but it would be better since i wouldnt have to conern about any nasty stuff to grow as the RO system fill the tank or the fermenter,



thank you for your help.