Harsh metallic/fusel taste

I just tasted a batch while transferring to a keg and it had an awful metallic and fusel taste. Never experienced these flavors before so not quite sure what happened, there were some unique things about this batch which I've listed bellow. The beer was a really basic American Pale Ale with White Labs WLP001. According to the BJCP Fault List the characteristics and causes are:

Metallic - Check water for metallic ions. Reduce water salts. Check equipment condition for rust. Make sure stainless steel equipment is properly passivated. Fully rinse sanitizer. Try using RO water and add salts as needed.

Fusel - Lower fermentation temperature. Pitch a sufficient quantity of healthy, active yeast. Check for infection. Try a different yeast strain.

There are three main suspects at this time:

1) Infection - Blowoff tube got pinched and the stopper was blown out. Took about a day for me to notice. The only time I've ever had an infection this is what happened, however it was an extremely sour/acidic taste and not a metallic/fusel. Thinking this is the most likely issue.

2) First time using copper HERMS coil - could this impact some off flavors? It was my immersion cooler before and never had any issues, but this was the first time wort was pumped thought it. I did not soak the inside with the white vinegar mix that I used on the outside.

3) First time building water from completely RO - I used the EZ_water_calculator spreadsheet that many people on here use and this is what I came up with for the american pale ale. At the time it seemed like quite a bit of minerals but I don't have much experience with salts to go by.



Thoughts on what was mostly likely the culprit? I'd hate to have another couple of bad batches due to my lack of understanding of water salts. Thanks guys.

I would say it's not infection from the data you have given. I've only had two infected batches so far and both had a cidery/vinegary taste and/or smell.

I use Bru'n Water for my salt additions and usually cut my tap water 50% with RO water. This leaves me with the following levels after I make my salt additions:

Ca: 44 ppm - 30 ppm added from CaCl and CaSO4
Mg: 10 ppm - no additions
Na: 30 ppm - no additions
SO4: 68 ppm - 37 ppm added from CaSO4 addition
Cl: 55 ppm - 26ppm added from CaCl addition

I'm far from an expert in water quality/brewing salt additions but your salt additions were much higher than mine and that is the most likely suspect to me. You used about 5x the CaCl and CaSO4 that I use for Pale Ales for the mash water alone and 7-10x the CaCL and CaSo4 in your Sparge additions.

If I were to use 100% RO water you would still be adding around 50% more salts to the mash and about 75% more additions to the sparge than I do. I'm guessing that may contribute to the metallic taste you are experiencing.

I suppose the HERMS Coil could have had an impact but I think that would be resolved now (therefore unrepeatable on your next batch) since the inside of the coil should now be passivated (if that is the correct term) with the wort you pumped through it.

If you haven't yet, give A Brewing Water Chemistry Primer a good read. A lot of good info in there.

I would also look into downloading Bru'n Water. Even if you prefer to continue using EZ Water, Bru'n water has some style profiles like Pale Ale, Amber, Yellow etc that can be a big help in hitting some target water profiles for the type of beer you are brewing. That combined with the Primer in the first link might alleviate your metallic taste.

As far as the fusels, at what temp did you ferment this batch?

The only time i have had these flavors was from the fermentation temp being too high- we went on vacation and when we got back the 'beer room' was 90*; beer was 88*. It had been that hot for over 5 days. The fusel alcohols were so intense it burned my nose when i smelled it.

What temp did you ferment at?

It could be a combination of factors. You did add a LOT of salts, which would probably be the cause of the metallic/minerally taste. The fusels could be from high fermentation temperatures and/or infection.

Looking at the spreadsheet, something seems really funky. How could you start with 0 alkalinity and end up with 179? Why add all that epsom salts and baking soda? Wierd. Next time, add just a bare minimum of salts, maybe 5 grams caCl2, and see if that improves the flavor. It definitely should.

Thanks for the responses.

My fermentation fridge was at 65 F the entire time so I doubt fermentation temperature is the problem.

Since switching to RO water about 10 batches about I've been using the Brewing Water Chemistry Primer method of sauermalz and calcium chloride to the batches but wanted to start building it entirely from scratch. Most of the beers I had during that period were good but seemed to be thin or lacking a body, I assumed the salts could help that out.

The alkalinity did throw me off but didn't notice it until brew day and forged ahead anyway. It may have been an error in the spreadsheet. I am playing with Bru'n Water right now and liking it quite a bit. Thanks for the recommendation.

Sounds like I just need to only use calcium chloride and gypsum and cut way down on them. I did add baking soda and salt to the boil and will not be doing that again. Even if the copper coil was an issue it shouldn't be in the future.

If I were starting with RO water and wanting to recreate the London water for a pale ale, which is:

Ca - 90 ppm
Mg - 5 ppm
Na - 15 ppm
SO4 - 40 ppm
CO3 - 125 ppm
CL - 20 ppm

What would be the best way to go about it? Just add 1-2 grams of Calcium Chloride and 2-3 grams of Gypsum to a 4 gallon mash? Then add a proportional amount to the boil? I know this is a very basic question but even after a ton of research I'm still having trouble wrapping my head about the water chemistry.

TonySwank said:

If I were starting with RO water and wanting to recreate the London water for a pale ale, which is:

Ca - 90 ppm
Mg - 5 ppm
Na - 15 ppm
SO4 - 40 ppm
CO3 - 125 ppm
CL - 20 ppm

What would be the best way to go about it? Just add 1-2 grams of Calcium Chloride and 2-3 grams of Gypsum to a 4 gallon mash? Then add a proportional amount to the boil? I know this is a very basic question but even after a ton of research I'm still having trouble wrapping my head about the water chemistry.

Click to expand...

Again, I am far from a water chemistry expert but from what I have read, I would not try to duplicate a specific region's water. We have no idea what type of treatment(s) they did to their water before they brewed with it. It would be like having a kid growing up and wanting to make a batch of dad's pale ale using your local tap water.

That said...if you are using 100% RO water and you plug the following numbers into the Water Adjustment Tab in Bru'n Water you will come very close to the London water profile. These are all in the grams per gallon column assuming a 5.5g batch with 4g of mash water:

CaSO4: 0.25g - adds Calcium and Sulfate
NaHCO3: 0.10g - adds Sodium and Bicarbonate
CaCl2: 0.25g - adds Calcium and Chloride
Pickling Lime: 0.25g - adds Calcium and Bicarbonate

I would leave the Mg alone since, again from my reading, it seems there is plenty of Mg in the grains and no need to any additional Mg. This also assumes you have added in your grains in the Mash Addition Tab of the spreadsheet. Darker grains have an effect on the acidity of the mash. Also, if you list your sparge water volume in the water adjustment tab, it will calculate how much to add to the sparge or boil.

Use caution when adding any Bicarbonate to your mash. I've only done it once so far and my mash pH ended up around 5.6 instead of the spreadsheet calculated 5.4 necessitating a couple of very small additions of Lactic Acid to drop the pH down a notch. Maybe I didn't let the mash sit long enough before testing the pH, maybe I measured incorrectly or maybe I made a mistake in the spreadsheet.

The above numbers show me needing a bit more Mash Acidity to get my mash pH down to 5.3. I use Lactic Acid instead of Sauermalz, so I would need to add .3ml per gallon of mash water or 1.2 ml total. I can't be much help with the Sauermalz additions since I have not used it yet.

Are you using a scale to measure your additions and a pH meter to check your mash?