Removing Metallic Flavors From Beer Using EDTA

My last batch of Bohemian lager had a distinctive metallic aftertaste which I traced back to a stainless steel scrub pad that I had placed at the base of the dip tube on my cornelius keg as a filter. The beer was fine until I racked it into the keg and added the filter... seemed like a good idea at the time. After about a day a very noticeable metallic aftertaste developed. I removed the stainless pad but the taste lingered.

EDTA is commonly used to chelate metallic flavors out of food products which can occur during processing. Specifically, Dow sells a product called Versene (I bought some plain old EDTA off of eBay, about $8 for 1lb). Large scale brewers may also use it as a foam stabilizer. It is added to many different food products as a color and flavor preservative. The Dow literature recommends 30 ppm concentration; it is safe in concentrations much, much higher.

Long story short, I added 500 mg to 19L of beer (about 1/4 teaspoon) and the metallic flavor disappeared instantly. Note: 1 ppm = 1 mg/kg. 19L = approx 19 kg. so 500 mg/19 kg = 26 ppm

Has anyone else tried this technique?

First I've ever heard of it, but it sounds like a good emergency technique. Maybe you can add it to the wiki?

Nice.

You can also add it to oxy clean and have something almost resembling a suitable detergent for brewing applications.

I wish I knew that a few batches ago. Wish there was a product to remove the taste of "burnt mash." Coulda used that this summer

You have to be carefull with it in nucleic acid purifications as it will chelate many enzyme cofactors used in later modification steps (ie. binding of Mg required for DNA polymerase). Oops... sorry, wrong forum

I think it does apply! That is apparently the mechanism for the preservative properties of EDTA... enzyme deactivation by chelating metallic co-factors. Not sure which beer bugs would be inhibited, though.

Gasman09 said:

I think it does apply! That is apparently the mechanism for the preservative properties of EDTA... enzyme deactivation by chelating metallic co-factors. Not sure which beer bugs would be inhibited, though.

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Specifically, EDTA chelates the iron, limiting the amount of iron solution inhibits all but the most pernicious bacteria. No iron, no cytochromes, no metabolism.
It would also limit the production of variety of DNA repair enzymes that contain iron-sulfur clusters, p53 being a good example in ecoli.

Did you add the free acid or the sodium salt?

Added the sodium salt.

Rushis said:

Specifically, EDTA chelates the iron, limiting the amount of iron solution inhibits all but the most pernicious bacteria. No iron, no cytochromes, no metabolism.
It would also limit the production of variety of DNA repair enzymes that contain iron-sulfur clusters, p53 being a good example in ecoli.

Did you add the free acid or the sodium salt?

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we use it to stop DNA or RNA polymerase reactions, as well as a preservative for plasmid DNA preps. EDTA will chelate Mg2+ which is required as a catalyst to bend the template DNA in to the proper configuration so the polymerase can bind and copy the template. At least thats what I remember from Bio-chem ten years ago.

When did you add the EDTA?

Is in the Keg too late?

hey

I tried the EDTA out. It works! I had a light beer that was crap from a strong metallic flavor, now it's much better.

I went with 30mg/L. Tried it out first on a 500ml batch by dissolving 1g of EDTA in 100ml of water and using 1.5ml. (1g/100ml = 10mg/1ml).

If you don't have a fine scale (luckily I have a scale accurate to 1mg (for reloading bullets)) you can work with small concentrations by using high dilutions.
Even a 10g amount, measurable on almost any digital kitchen scale, in one litre (1000ml) will give you 10ml/ml. This allows you to accurate add, say, 500mg by using 50 ml of solution.

Cheers!~

pjj2ba said:

You have to be carefull with it in nucleic acid purifications as it will chelate many enzyme cofactors used in later modification steps (ie. binding of Mg required for DNA polymerase). Oops... sorry, wrong forum

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Maybe you can use Tris instead of 5.4 in your mash...

/Science is cool

I can't guess what process you invoked to say that that a SST scrubby was the cause of the metallic flavor.

Yeast can produce a wide range of odd flavors. It all depends on the circumstances in which they live.

Adding EDTA to you beer will act in the reverse manner of a yeast nutrient.
Yeasts need minerals EDTA binds to minerals making them unavailable for the yeast. That's why it's used in things like Mayonnaise it locks up the minerals and serves to prevent bacteria and mold.

How much EDTA will starve the yeast is anyone's guess. I'd say it all depends on the quantum of minerals and EDTA

Cliff897 said:

I can't guess what process you invoked to say that that a SST scrubby was the cause of the metallic flavor.

Yeast can produce a wide range of odd flavors. It all depends on the circumstances in which they live.

Adding EDTA to you beer will act in the reverse manner of a yeast nutrient.
Yeasts need minerals EDTA binds to minerals making them unavailable for the yeast. That's why it's used in things like Mayonnaise it locks up the minerals and serves to prevent bacteria and mold.

How much EDTA will starve the yeast is anyone's guess. I'd say it all depends on the quantum of minerals and EDTA

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Good point, but I imagine using EDTA after fermentation is complete shouldn't change any thing.

Is there anything I should look for when shopping for this stuff? I don't want to get the wrong stuff. I just went to keg a recent batch and it has the strangest metallic, spicy funky flavor. I've never had this happen before, but it's a 10g batch and I'd love to salvage it.

I have another solution. It's called TIME. I've had a couple of batches with a very strong metallic flavor. 3 - 4 weeks later, the off flavor had completely gone.

-a.

bmbrewery said:

Is there anything I should look for when shopping for this stuff? I don't want to get the wrong stuff. I just went to keg a recent batch and it has the strangest metallic, spicy funky flavor. I've never had this happen before, but it's a 10g batch and I'd love to salvage it.

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Metallic flavors don't necessarily come from metal, unfortunately. But - if it is metal that is the problem EDTA is very effective. It doesn't hurt to try, starting with small doses and working your way up to 40ppm. Just look for 'food grade' EDTA. I got mine on Ebay.

ajf said:

I have another solution. It's called TIME. I've had a couple of batches with a very strong metallic flavor. 3 - 4 weeks later, the off flavor had completely gone.

-a.

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LME porter, kegged, star san, yeast nutrients.

I panicked a few days ago because a 3 week old porter had massive metallic flavors and went on a licking binge taste testing all my equipment. 3 days later (not kidding) I tasted the porter again and the metallic flavors are gone.

OMGRDWHAHB

My previous brew, a Belgian amber, also had metallic flavors at first but diminished by the end of the keg. I just figured it was the new immersion chiller.

EDTA is also used for individuals with lead poisoning, FYI

lead tastes sweet... that's why kids will keep sucking on an old painted window sill.

Did the stainless steel scrubby have any signs of corrosion? If not, it's highly unlikely that was the source of your off flavour. The entire corny keg, afterall, is made of stainless steel too.

I just found out that FFL swivel nuts are plated brass, as are the MFL threads on ball locks. Long term exposure to StarSan eats the plating off, which subsequently stays in my StarSan vat. I draw from this vat for all my sanitizing. Most of my siphon tubes and canes are in this vat.

OOPS.

I came across this post a few weeks ago after having a metallic taste in an IPA that I had dry hopped in a corny keg. I had hung two stainless steel tea balls off of a hose clamp fixed to the pressure relief valve on the keg. The hose clamp broke and fell into the keg during the dry hop. I thought the clamp was SS, but when I carbed up the beer, there was a strong metallic aftertaste. I opened the keg and fished out the clamp and the screw was corroded (apparently only the band was SS).

I assumed I was going to have to dump it until I came across this thread. Ordered EDTA supplements online and dumped the contents of 1 pill (625 mg) into the keg last night, pressurized it and shook it gently to mix the powder in, and tapped it. Just like gasman09 said, the metallic taste was instantly gone.

Thanks for the post, you saved 5 gallons of beer from the drain. I owe you a few.