Forgot the Campden tablet again

[Dave Parry]

I need to hook up a reminder when I am filling the hot liquor tank as there is a 50-50 chance that I will forget the Campden tablets, which I did again this weekend.
I realise it is there to take the chlorine out of the water to avoid it reacting badly with the malt.

Can anyone describe the flavour though that you get when it happens? I’m not sure if any of flavours I am sensing are because of this or potentially from something else.

 

[marshbrewer]

I think it's the yeast that chlorine reacts with; the off flavours are a medicinal TCP taste in the resultant beer.

 

[glennturner83]

I think it's the yeast that chlorine reacts with; the off flavours are a medicinal TCP taste in the resultant beer.

Doesn't react with the yeast...it kills it. That is the reason chlorine is added to water; to kill bacteria and other microorganisms. However the amount in water will not kill all the yeast but just inhibit it's reproduction.

The TCP taste you describe is more likely from chlorophenol that is present in water from pesticide contamination rather than added chlorine. Probably more likely a problem in crop growing areas than cities. The bisulphite from campden tablets will mop up free chlorine but you will still have the phenol. Best bet if you get TCP like taste a lot would be to use bottled water to run all your water through a filter.

 

[marshbrewer]

My understanding that the presence of chlorine in the water during fermentation causes the production of trichlorophenol ?

 

[glennturner83]

I have seen that before on forums etc but never seen an academic paper saying it. I can't see why it would. There is no biological reason or process I can think of that would lead to a yeast cell making a small, aromatic molecule. Esters...yes. Ethanol...yes. Trichlorophenol...nah. The process is called electrophilic halogenation and would probably require a an acid catalyst (google it).
I may be wrong as I am approaching this as a chemist, not a microbiologist. Just seems more likely that this is a another brewer's old wives tale

 

[strange-steve]

The yeast doesn't produce the trichlorophenol, it is formed through the reaction of free chlorine in the water with phenols in the wort from malt, hops, and to a lesser extent yeast. Which bit are you dubious about?

 

[glennturner83]

I think it's the yeast that chlorine reacts with; the off flavours are a medicinal TCP taste in the resultant beer.

This is the bit I am dubious about!

You are suggesting something different and plausible.

 

[strange-steve]

Well I don't want to speak for jjsh but I suspect he meant yeast produced compounds rather than the yeast itself. The production of trichlorophenols in the brewing process is a fairly well known and understood phenomenon I believe.

 

[glennturner83]

I think you may have just underlined my point about it being an old wives tale. Does anyone on here have membership of the institute of brewing or anything similar where they can access research? All the journal references I have access to only talk about testing techniques with vague references to chlorophenol being formed as a result of using chlorine based sanitisers, not chlorine in the water. And they are all very dated.

 

[strange-steve]

I think you may have just underlined my point about it being an old wives tale. Does anyone on here have membership of the institute of brewing or anything similar where they can access research? All the journal references I have access to only talk about testing techniques with vague references to chlorophenol being formed as a result of using chlorine based sanitisers, not chlorine in the water. And they are all very dated.

Again I'm not really sure which bit you're dubious about. Is it that there is no chlorine and/or phenols present? Is it that they're not present in enough quantity? Is it that they won't react? Is it that they won't react in wort? Is it that the reaction won't produce an off-flavour compound?

 

[itry]

Being the man who has made quite a bit of TCP recently i can confirm that the TCP flavour is (im 99% sure) bad cleaning and bad sanitation and possibly not cleaning the cleaner out of the tank properly. I have made a lot of good beer with untreated water. If you leave my water over night it does smell like a swimming pool. I now use a Camden tablet with my water and the clean my tanks differently. The first time i used a camden tablet i made TCP .

 

[strange-steve]

I think we're getting a little distracted but just to clarify some points, there is usually very little free chlorine in tap water (often <1ppm) and so the risk of not treating with metabisulphite is quite low but not zero. It doesn't take much chlorophenol to produce a noticable off-flavour (a few ppb will do it) and Campden tablets are such a quick and easy insurance against this that I always recommend their use, but I wouldn't worry too much if I forgot to use it.

A much bigger risk is not properly rinsing chlorine-based sanitisers. Treating your mash and sparge liquor with Campden tablets obviously won't protect against residual chlorine from your sanitiser left in or on your equipment.

A third source of phenolic off-flavours is wild yeast contamination, some of which create a ton of phenols, which can be spicy clove in small amounts but nasty and medicinal in higher quantities.

I'm not sure which bit of this glennturner thinks is an old wives tale but I've never heard another brewer (including chemists and microbiologists) doubt this.

 

[An Ankoù]

Strange-steve is spot on. There are several sources of chlorophenol off flavours and they have a very low taste threshold. As the OP is worried about forgetting to put a Campden tablet in his sparge water then it's the presence of chlorine in tap water that he's concerned with. The fact that many brewers can get away with untreated water is irrelevant. If the water supplier relies on free chlorine then leaving it overnight or boiling the water first will get rid of it. If the supplier uses chloramine, boiling won't get rid of it and your beer will be ruined. A Campden tablet will easily resolve either issue quickly and cheaply. Why take the risk?
Chlorination here is uneven; sometimes it's undetectable and other times it smells like a swimming pool.

 

[Dave Parry]

I’ve triggered more of a discussion on this than I imagined. I’m always impressed at the quality of debate on here. Thanks everyone.

I suppose in essence, the practical question I have is, having forgotten to put the campden tablet in before the mash, is there any way I can recover the situation - or is that it now? If I put a tablet in during fermentation it is going to inhibit the yeast action.

From the helpful comments above I think I can just relax and not worry about it too much - just try to remember next time.

Thanks everyone

 

[An Ankoù]

I’ve triggered more of a discussion on this than I imagined. I’m always impressed at the quality of debate on here. Thanks everyone.

I suppose in essence, the practical question I have is, having forgotten to put the campden tablet in before the mash, is there any way I can recover the situation - or is that it now? If I put a tablet in during fermentation it is going to inhibit the yeast action.

From the helpful comments above I think I can just relax and not worry about it too much - just try to remember next time.

Thanks everyone

If you put the Campden tablet into the wort before you boil it with the hops it would go a long way to ensuring that no hop phenols become chlorinated. What happens in the mash at mash temperature between chlorine and the tannins present in the malt husks (which are polyphenols) I have no idea.