Sodium Met. & Chloramine

[jakub76]

I've just started fiddling with simple water chemistry based on John Palmer's How To Brew. I'm adjusting my residual alkalinity based on my water report to match the style of beer I'm making - adding a measure of Gypsum for light lagers or a measure of Bi-Carb for darker beers. I've done the maths and drawn the charts...fun in a geeking out on beer kind of way.

My question though relates to using sodium metabisulfite to neutralize the chloramine in my water. In the inner west of Sydney I have 0ppm Chlorine but 1.1ppm Monochloramine. Although I haven't noticed off flavours I'd still like to try and neutralize it in order to make the best beer I can. I understand campden tablets do that job, they are caked Sodium Metabisulfite...so my question is -

How much Sodium Met do I add to my mash water (15 litres strike and 23 litres batch sparge) to properly neutralize the chloramine? How long do I have to wait for it to act? Do you do this and have you noticed any side effects?

I have done some reading already and several searches including this thread http://www.aussiehomebrewer.com/forum/inde...showtopic=13336
Screwy do you still use a pinch in your HLT? Would a pinch be around 1/4tsp, how long do you wait for it to work its magic?

Cheers

EDIT: I realise a carbon filter would sort it out but that is not financially an option at the moment

 

[Kai]

I used to religiously add a very professionally measured pinch to my mash and sparge liquor as they were heating up. That was generally sufficient to knock out the chlorine in Adelaide water, but it's not a very precise measurement, sorry!

 

[jakub76]

Thanks Kai,
A pinch seems to be the universal measurement :icon_cheers:

 

[jakub76]

Looking through some wine making forums there seems to be a consensus that 1 campden tablet equal 1/16 tsp, some say 1/12 tsp based on calculating the residual sulphur dioxide in wine must.

John Palmer suggests that 1 campden tablet treats 20 gallons/75 litres.

So to treat the 38L that I need for my system I suppose I would use 1/2 a tablet or 1/32 tsp (or 1/24 depending on who's advice you take).

Any tips on measuring such a small amount? How long does it need to neutralize the chloromine? Is it pretty instant, does heat effect it? What does it turn the chloromine into?

 

[Noxious]

Check out this book link

Equation 10, should be the one.
The actual reaction process is probably more complicated than this though, also there will be residual sodium compounds which may not be desirable.
Hope that is of some help

 

[RetsamHsam]

Any tips on measuring such a small amount?

A pinch between the thumb and index finger should be equal to 1/24 teaspoon, between the thumb and pinky is 1/32 teaspoon :lol:

 

[benno1973]

John Palmer suggests that 1 campden tablet treats 20 gallons/75 litres.

Yep, I use a 1/2 campden tablet per 40L water to be treated. Not sure what that works out to in powder form though. I've always assumed that that works pretty much instantly.

 

[jakub76]

Noxious thanks for the book link. Interesting to know that it also scavenged O2. I'd imagine the small amounts of the by products wouldn't be signifcant. How did you work out your amounts in the last post? 2 grams seems a lot, I believe a campden tablet is around 0.7g so that would be like 3 tablets for a batch instead of a half as recommended in How To Brew.

EDIT: campden tablets weigh 0.44 grams each apparently. So I guess a half tablet for one batch would be 0.22 grams of Sodium Met

 

[KillerRx4]

I add 1g to 50lt in hlt.

 

[Noxious]

PM sent.

 

[zoigl]

PM sent.

Any tips on measuring such a small amount? :huh:

I would have a go at measuring the smallest amount my scales could handle

then pour the powder (assuming that it has been pulverised to a powder in a mortar and pestle) onto a sheet of clean A4 paper

then divide it in half with a sharp knife or steel spatular

then divide.....etc etc until I got the approx amount I was looking for

just my 2 bobs worth,
good luck

 

[zoigl]

PM sent.

Any tips on measuring such a small amount? :huh:

I would have a go at measuring the smallest amount my scales could handle

then pour the powder (assuming that it has been pulverised to a powder in a mortar and pestle) onto a sheet of clean A4 paper

then divide it in half with a sharp knife or steel spatular

then divide.....etc etc until I got the approx amount I was looking for

just my 2 bobs worth,
good luck

 

[zoigl]

PM sent.

Any tips on measuring such a small amount? :huh:

I would have a go at measuring the smallest amount my scales could handle

then pour the powder (assuming that it has been pulverised to a powder in a mortar and pestle) onto a sheet of clean A4 paper

then divide it in half with a sharp knife or steel spatular

then divide.....etc etc until I got the approx amount I was looking for

just my 2 bobs worth,
good luck

 

[jakub76]

Hey Vespa2,
Thanks for your message(s). I like your thinking, perhaps a credit card and a mirror is what I need, I'll take a 1/4 tsp onto the mirror and cut it into 8 lines B)