Campden tablet misinformation?

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ultraplop

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This is kind of a rambling rant, but I hoping someone might be able to tell me if it sounds right or if I am misunderstanding the situation. I also had a question at the bottom if anyone knows:

I recently followed the directions in a BYO article to dechlorinate brewing water and after doing further internet research, I am pretty sure the BYO article is way off and I added way too much sodium metabisulfite to my brew.

Here is the article.

The dechlorination reaction requires 1.47 mg of sodium metabisulfite to reduce 1 mg of free chlorine. In practice, this ratio is increased two–three fold. In easy to use terms, a 1/2-ounce Campden tablet can be used to dechlorinate 20 gallons

link: http://***********/stories/wizard/a...ing-chloramine-a-historical-hopping-mr-wizard

Mr. Wizard states that 1/2 ounce of sodium metabisulfite will dechlorinate 20 gallons of water. He also stated that this was one tablet. After doing the market research I found that pretty much all campden tablets that you can buy are actually only 550 mg or 1/50 of an ounce. However, before I realized that, I assumed that the tablets came in multiple sizes and I adjusted for my brew water based off of the weight stated in the article. I estimated 1/5 of an ounce for 7 gallons. That should have been at least 10 tablets, but my scale might be off because I ended up measuring out and adding 7 tablets to 7 gallons. Interestingly enough, that is the ratio that the bottle recommends for sterilization.

After reading more HBT threads on the subject (and reading the label), it seems that I should have used less than one tablet total. And also, doing the math in the BYO article shows that Mr. Wizard may be contradicting himself and that the article might have a fairly significant typo. 1.47 mg of SMS per 1 mg chlorine is only 38 mg for 26 Liters or 7 gallons. Scaled up for chlorine content of 2 - 4 mg/l, that is still only 76mg to 153 mg total. Mr. Wizard is off by at least a factor of 10 when he says to use 1/2 ounce for 20 gallons. It looks like that could be a typo and should say 1/2 gram for 20 gallons. That would make sense and match closely to his 1.47 to 1 ratio.

Anyway, so yea I put in 7 tablets for 7 gallons which is 3850 mg; so its a little higher than the 150mg I actually needed. My first concern was that the yeast would not survive or have a very hard time in the wort. However, this morning it looks like the yeast are fermenting the wort quite well. There was about 8 hours of time from when the water was treated and the yeast was pitched and as I understand it, the metabisulfite will be removed from the solution after a certain amount of time (24 hours is how long wine makers go). Perhaps 8 hours was long enough for it to get to safe levels. The wort was of course also boiled and I'm not sure if that also has an effect.

So is that a technical error in the BYO article? They are actually calling for numbers higher than even what I put in which would be beyond sterilization levels and leaving out the fact that you are supposed to wait 24 hours.

I also had another question if anyone knows, I couldn't find anything specific on this:

What does the sodium metabisulfate leave behind; anything that affects your water profile? I would guess there may be a certain amount of sodium. I also read a HBT thread that stated that the sulfite gets converted to sulfate. If this is true, anyone know how much of these compounds are present? Would it affect your chloride to sulfate ratio?
 
Yeah, way too much. Everything I have ever read tells me that one (1) campden tablet will treat 20gal. of water. I use 1/2 tablet per 10gal. of water. I crush a whole tablet, reserve half and split it off to what I need for mash and sparge. A littel nore here and ther is no big deal, but more than one tablet for a 5gal. batch is overkill.

I'm not sure on your other questions - maybe a water geek -er, guru, will help out.
 
Yeah, what Rhoobarb said. 1 tablet is indeed enough to treat 20 gallons, so I tend to crush up 1/2 of a tablet and treat my mash/sparge water all at once.
 
You're mixing up some terms here. Potassium (or sodium) metabisulfite is a powder. It is used in VERY small doses for dechlorinating water, and as an antioxidant in wines, as well as a preservative. For sanitizing, the dosage is much larger.

Campden tablets are a convenient form of K meta (or Na meta) but the tablets are NOT pure k meta. They have binding agents and the like, so that you get approximately 50 ppm free so2 for wine making. That translates to roughly one campden tablet per gallon for antiseptic properties. It is NOT interchangable with k-meta powder.
 
This seems nitpicky, but it's NOT 24 hours before sulfites dissipate. It's actually over a very long period of time. That's why you can add sulfites at bottling- it'll gradually lower but stay high enough to preserve the wine for a long time. I add approximately 50 ppm of K-meta at every other racking for wine (I don't use Na meta, as it WILL leave sodium in the wine) which will last several months. So, the idea that the sulfites will be gone in 24 hours is flawed.
 
You're mixing up some terms here. Potassium (or sodium) metabisulfite is a powder. It is used in VERY small doses for dechlorinating water, and as an antioxidant in wines, as well as a preservative. For sanitizing, the dosage is much larger.

Campden tablets are a convenient form of K meta (or Na meta) but the tablets are NOT pure k meta. They have binding agents and the like, so that you get approximately 50 ppm free so2 for wine making. That translates to roughly one campden tablet per gallon for antiseptic properties. It is NOT interchangable with k-meta powder.

Yeah the BYO article doesn't explain that.

But that does explain why most sources list campden tablets as .44g of K or Na Metabisulfite. I was wondering why they said .44 when the tablet was more like .55g.

So that would mean that 1/2 ounce of campden is equal to 6.6 grams of sodium metabisulfite and you only need 440 mg for 20 gallons. Mr. Wizard is still way off.
 
You are thinking too hard. I crush one caplet and add the whole thing to 12+ gallons of strike all at once. I also use the whole thing in much smaller mashes. I have not noted any issues.
 
You are thinking too hard. I crush one caplet and add the whole thing to 12+ gallons of strike all at once. I also use the whole thing in much smaller mashes. I have not noted any issues.

I disagree I have plenty to worry about considering that campden can stop or at least help stop fermentation. Read this: http://www.ehow.com/how_5627060_stop-fermentation-wine.html

That is how much campden I put in. You put in one tablet for 12 gallons, well if you put the same ratio that I put in, it would have been 12 tablets. (1 tablet per gallon).

It is true though that the yeast in my batch are actually going pretty well. I am not sure though if they are stressed out or whether a significant amount died, which may result in off flavors. Only time will tell.
 
In Brewing Classic Styles, John Palmer says that "One tablet will treat 20 gallons, although using 1 tablet for only 5 gallons won't hurt anything. Both chlorine and chloramine are reduced to insignificant levels of sulfate and chloride ions (<10 ppm) within a couple of minutes at room temperature."
 
Hey, get off his case! He meant a METRIC 1/2 ounce.

eh? you mean a mounce? lol

To be honest I'm not sure how much that would be. i did some googling and this:

http://www.diracdelta.co.uk/science/source/m/e/metric ounce/source.html

states that a mounce is is 25 grams which is 3 grams less than a standard ounce. Not big enough difference to matter for this discussion.

Also on wikipedia, apparently a dutch metric ounce is 100 grams. (I'm glad I didn't use that measurement)

Also I mean come on, I expect standard measurements from BYO. Nobody uses metric ounces that I have ever heard of. Just like if BYO calls for a gallon of something, I expect US Gallons, not Imperial gallons or some other random measurement. If they are going to use non standard measurements, then they should probably state that in the article so people know what they are talking about.

Maybe you are being sarcastic; I can't tell.
 
I guess sometimes you have to take things with a grain of salt, especially when the picture next to the article shows the author with a beer in his hand and hes wearing a silly hat.
 
Yeah, way too much. Everything I have ever read tells me that one (1) campden tablet will treat 20gal. of water. I use 1/2 tablet per 10gal. of water. I crush a whole tablet, reserve half and split it off to what I need for mash and sparge. A littel nore here and ther is no big deal, but more than one tablet for a 5gal. batch is overkill.

I'm not sure on your other questions - maybe a water geek -er, guru, will help out.

Hey, just to make things clear, and make sure everyone is on the same page, how big are you tabs? I am going to be using the tabs from the bottle in the picture. When I begin my first AG batch in a couple of days I want to make sure I am not adding too much or too little. BTW there is no marking on the bottle that lists the size of tab in the bottle.

campdenTablets-e1275175878535.jpg
 
I don't have any information on my tablets, it came in a white bag from my homebrew store, with a label they made that says Campen, use 1 per gallon...so I'm assuming I should follow that...but after reading this thread I'm a little nervous that I used so many per batch. My fermentation has all started out well, so I assume all is well, but wanted to see if I could get a little clarification, or if I should just call my LHB store when they open again.
 
I don't have any information on my tablets, it came in a white bag from my homebrew store, with a label they made that says Campen, use 1 per gallon...so I'm assuming I should follow that...but after reading this thread I'm a little nervous that I used so many per batch. My fermentation has all started out well, so I assume all is well, but wanted to see if I could get a little clarification, or if I should just call my LHB store when they open again.

If you're making wine, the proper dosage is one campden tablet (crushed) per gallon of wine.

If you're treating brewing water to get rid of chlorine, the dosage is less.
 
If you're making wine, the proper dosage is one campden tablet (crushed) per gallon of wine.

If you're treating brewing water to get rid of chlorine, the dosage is less.

Beer, all grain to be specific. I put in 1 per gallon for my strike and sparge water, and then heated the water to the proper temp for my mash and sparge.

Will I be looking at off flavors from this? Fermentation started no problem for all the beers I've made with them, but won't be able to try one of them for around two weeks when the first is done.
 
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