Potassium Metabisulfite Question

[Bigtex2884]

So I have read some, probably not all, threads on PM/campden tabs being used to rid tap water of Chloramines. My question is if you add too much does the excess get boiled off or will there be residual yeast killing compounds still in the wort after the boil that would not allow fermentation after pitching the yeast and kill them?

 

[mabrungard]

Excess metabisulfite is decomposed during the boil, so you don’t need to worry for your yeast. However, you don’t want to overdose since it adds ionic content that may not benefit the beer.

 

[Bigtex2884]

Okay thanks so in beginners words. It may make it taste different than intended and the boil will neutralize any yeast killing potential by the time it makes it to the fermenter.

 

[RPh_Guy]

Excess sulfite will be removed via oxidation in the mash (or even before then). Boiling does NOT get rid of sulfite.

Also, you would need crazy high levels of sulfite to inhibit yeast at beer pH.
https://modernbrewhouse.com/wiki/Sulfite#Microbial_Effects_in_Beer

In other words, just use as directed and there's nothing to worry about.

 

[Bigtex2884]

So with this would I follow the to kill wild yeast or to sanitize?

 

[RPh_Guy]

So with this would I follow the to kill wild yeast or to sanitize?

You can use it as a no-rinse sanitizer. It should be used with an acid to increase efficacy. A good recipe is 1 Tbsp of the sulfite plus 1 Tbsp of citric acid in 1 gallon. This solution would only be effective for maybe 24 hours or so. However it's probably not the best option for sanitizing compared to other products.

Besides a small amount for chlorine removal or low oxygen brewing, sulfite generally isn't useful for making beer.

 

[Bigtex2884]

I only want to use it as a way to get rid of Chloramines. I added a tablespoon of it and citric acid and added it to 14 gallons of water and ended up with 12ish in my fermenter.

 

[RPh_Guy]

... You added 1 Tbsp of the sulfite and citric acid to your strike water?

To treat 14 gallons of water for chlorine you need less than half a gram of potassium metabisulfite, and no citric acid.

Chlorine removal has nothing to do with sanitation.

Sorry for any confusion. You're going to want to aerate that thoroughly to make sure all the sulfite gets oxidized.

 

[doug293cz]

I only want to use it as a way to get rid of Chloramines. I added a tablespoon of it and citric acid and added it to 14 gallons of water and ended up with 12ish in my fermenter.

A tablespoon is way too much. You only need about 200 - 225 milli grams for each 10 gal of water to neutralize chlorine/chloramine. A single Campden tablet is about 440 mg and will treat 20 gal of water. You should either use tablets, or an accurate scale for adding Kmeta.

Brew on

 

[RPh_Guy]

You only need about 300 - 350 milli grams for each 10 gal of water to neutralize chlorine/chloramine.

How'd you get those numbers?

 

[Bigtex2884]

I did shake the crap out of it one in the fermenter To oxygenate it and when I transferred it from the boil kettle to the fermenters I did a slow high transfer. I only added the acid blend to bring down the ph to around 5.6. I have pretty hard tap water like 8+.

the damage is done so to speak so what negatives am I potentially looking at. Fermentation has slowly started today and I pitched last night around 6pm.

 

[doug293cz]

How'd you get those numbers?

I edited them down a bit after double checking the contents of a Campden tab. @ajdelange went thru the derivation of this somewhere in the "Brew Science" forum.

Edit: Found the source.
Brew on

 

[RPh_Guy]

That'll generate about 200ppm of sulfate, which may throw off the mineral profile. Sulfate tends to enhance bitterness and dryness.

If there's any unoxidized sulfite when you pitch yeast, you made get a sulfurous aroma and possibly poor fermentation performance.

@doug293cz Looks better.

 

[Bigtex2884]

Well it’s a lemon shandy so I’ll let y’all k ow in about 4 weeks. OG was 1.050 so we shall see how those yeast munch.

 

[VikingBrewer]

So I’m trying to wrap my head around all this and I’m a bit confused. Doesn’t take much .

So I have a pack of the Spagnols Potasium Metabisulphite. Acquired this in a wine equipment kit I bought.

So is this used to rid your water of chlorine/chloramine or is it used for a no-rinse sanitization? Both??? I don’t get how it can be both.

I’m not a fan of using added chems so I’m reluctant to use this.

If used to rid chlorine/chloramine, what’s the process? Add to water (for how long) then boil the water before adding extract and fermetables (or all grain ingredients) or no need to boil?

 

[VikeMan]

So is this used to rid your water of chlorine/chloramine or is it used for a no-rinse sanitization? Both??? I don’t get how it can be both.

It can be used for both. When used as a sanitizer, the concentration of metabisulfite is higher than when treating water for chlorine/chloramines.

If used to rid chlorine/chloramine, what’s the process? Add to water (for how long) then boil the water before adding extract and fermetables (or all grain ingredients) or no need to boil?

You just add it to the water and dissolve. Done.

 

[VikingBrewer]

When used as a sanitizer, the concentration of metabisulfite is higher than when treating water for chlorine/chloramines

If used for Sanitation, best practice to sanitize a 23L fermenter, use 1-2 gallons or fill and add accessories inside?
How does it compare with Star San?

You just add it to the water and dissolve. Done.

What quantity per liter or gallon for sanitation vs dechlorinization?

 

[VikeMan]

How does it compare with Star San?

Star San is easy and reliable, which is why so many people use it. I can't think of any brewers I know off hand using K-Meta for sanitizing. I think a lot of winemakers do though, maybe because it also has other uses in winemaking.

What quantity per liter or gallon for sanitation vs dechlorinization?

I believe it's 2 oz per gallon of water for sanitizing. But that's going off of memory and I don't use it for sanitizer, so I'd recommend verifying. Or do what @RPh_Guy says in post #6.

 

[Vale71]

How does it compare with Star San?

StarSan is a sanitizer and is somewhat effective, metabisulphite is not and will have no effect as regards sanitation.

 

[VikeMan]

StarSan is a sanitizer and is somewhat effective, metabisulphite is not and will have no effect as regards sanitation.

If this is true, there are thousands (millions?) of winemakers fooling themselves.

 

[Vale71]

If this is true, there are thousands (millions?) of winemakers fooling themselves.

No their not, you're just mixing up sanitation of surfaces with sanitation of wine must. The question I responded to referred to sanitation of surfaces and for that a simple metabisulphite solution is about as effective as tap water.

 

[VikeMan]

No their not, you're just mixing up sanitation of surfaces with sanitation of wine must. The question I responded to referred to sanitation of surfaces and for that a simple metabisulphite solution is about as effective as tap water.

No, I'm not confused. I'm saying that many winemakers use metabisulfite for sanitizing equipment. They use it at a much higher concentration than for wine must.

 

[Vale71]

If they're doing it right they're also mixing it with an acid such as citric to lower PH below 3.0 in order to release SO2 which is indeed a sanitizer. Just filling your fermenter with a metabisulphite solution will not achieve anything and is only a waste of time and material.

 

[RPh_Guy]

If they're doing it right they're also mixing it with an acid such as citric to lower PH below 3.0 in order to release SO2 which is indeed a sanitizer. Just filling your fermenter with a metabisulphite solution will not achieve anything and is only a waste of time and material.

Do you know the pH of 2oz/gal (15g/L) potassium metabisulfite in water?

 

[VikingBrewer]

Do you know the pH of 2oz/gal (15g/L) potassium metabisulfite in water?

I just used this formula today “for sanitation” of my bottles, it’s what came up when I googled the ratio to sanitize. Usually I used a teaspoon of bleach to 4 liters and rinse thoroughly.

 

[barada83]

Extended boiling such as what is done during the boil removes chlorine and choramines from tap water. Chlorine has no impact on amylases It’s a waste to add metabisulfate to tap water prior to mash etc. if you are topping up after the boil or something then it might be more applicable. But then it’s also probably dilute. Sulfates and sulfates are used to inhibit microbial growth. Extensively in wine, smoking meat, and sausage making.
Chlorine does nothing negative to the mash I terms of amylase activity, nor does it chemically interact with anything else to form permanent compounds. I’d recommend skipping the campden prior to the boil.

 

[VikeMan]

Chlorine does nothing negative to the mash I terms of amylase activity, nor does it chemically interact with anything else to form permanent compounds. I’d recommend skipping the campden prior to the boil.

It sounds like you're saying that chlorine/chloramines in the mash will not react with phenols from the malt to form chlorophenols. Why would that be the case?

Extended boiling such as what is done during the boil removes chlorine and chloramines from tap water.

Until all of the chloramines have boiled away (if in fact they all do), what prevents them from forming chlorophenols in the boil?

 

[doug293cz]

Extended boiling such as what is done during the boil removes chlorine and choramines from tap water. Chlorine has no impact on amylases It’s a waste to add metabisulfate to tap water prior to mash etc. if you are topping up after the boil or something then it might be more applicable. But then it’s also probably dilute. Sulfates and sulfates are used to inhibit microbial growth. Extensively in wine, smoking meat, and sausage making.
Chlorine does nothing negative to the mash I terms of amylase activity, nor does it chemically interact with anything else to form permanent compounds. I’d recommend skipping the campden prior to the boil.

Do you have any references for chlorine/chloramine not reacting in the mash/boil to form chlorophenols?

Brew on

 

[barada83]

It sounds like you're saying that chlorine/chloramines in the mash will not react with phenols from the malt to form chlorophenols. Why would that be the case?

The reality is that this is pretty advanced organic chemistry. Chlorophenols are formed via specific reactions efficiently which are known. Check out this link which is the easiest to understand. :phenol | Definition, Structure, Uses, & Facts

The fact is that the mash or boil has neither the catalyst, the temp, or the supply of the raw materials to do much of anything to form chlorophenols. It is not just a magical reaction that occurs when phenols and chlorine are potentially present but is much more complex. Especially in anything less than industrial scientific situations where chlorine gas is available at 100% concentration. Note the reactions and the conditions required.

Phenols are a pretty present reality in life. Many smells are phenol based, not pure phenol but a phenolic ring forming the basis of an aromatic compound. Phenols are definitely a potential for off flavors. Phenols are present in the malt and are created through yeast during fermentation. I really really doubt that those are caused by chlorophenols for all of the above reasons. There are brewing science papers but I have not seen one that addresses the off flavor of chlorophenols due to municipal chlorination. I'd check the off flavor phenols caused by wild yeast or bad temps before running down the chlorophenol route.

Just to be clear, I'm not doubting that if you did an HPLC of the beer that you wouldn't find chlorophenols, its just that the presence would be for all practical purposes completely undetectable.





Until all of the chloramines have boiled away (if in fact they all do), what prevents them from forming chlorophenols in the boil?

Chemistry

 

[RPh_Guy]

Does boiling remove chloramine?

Edit: I see that it does.