Lacto infection... in my coffee maker?

[strange-steve]

This is an odd one, but a few days ago a made a coffee in my little moka pot as I do every morning, and as I was about to take the first sip I got a definite whiff of lactate (think sour milk, although the coffee was black). I took a sip anyway and yep, definite lacto sourness making the coffee really quite unpleasant. I went to the moka pot and had a sniff inside and again the same sour milk aroma.

So I took the thing apart, soaked all the pieces in oxyclean, then put another oxyclean solution in the bottom and boiled it up through on the stove, give it a good rinse and made another coffee in it. Same sour twang as before but not quite as strong. So I took it all apart again to make sure I hadn't missed anything, give it another good rinsing with hot water and tried again. Same thing.

Just to make sure it wasn't the coffee beans I made another coffee this time in the French press and it came out perfect. I can actually still smell that nasty lacto twang from the bottom part of the moka pot several days later, even though it's been thoroughly cleaned several times. Any idea what's going on here?

 

[MyQul]

One of the weirder things I've read on a brewing forum (apart from Drunkula's posts of course). How could it possible get in your coffee pot? Can the Lacto bacteria attach to dust and travel airborne that way?

 

[strange-steve]

I have no idea, plus the thing is cleaned and then literally boiled on the stove everyday

 

[MyQul]

I googled whether lacto can travel through the air on dust and this came up. I dont seem to be able to highlight the relevant part but if you go to the very top of page three it talks about microorganisms traveling through the air

can lacto bacteria travel airborne - Google Search its the second hit down

 

[Session]

I googled whether lacto can travel through the air on dust and this came up. I dont seem to be able to highlight the relevant part but if you go to the very top of page three it talks about microorganisms traveling through the air

can lacto bacteria travel airborne - Google Search its the second hit down

Interesting idea, but I think the cause of the sour smell is very unlikely to be lactobacillus. It would be a highly unusual strain to be able to survive the high temperatures the metal would be heated to whilst making coffee (they are destroyed at temperatures over 57’C).

You can get a sour profile if under-extracting espresso. Oils can also accumulate under seals etc and oxidise, giving a sour/bitter smell/flavour.

It sounds as though everything is nice and clean now, and given the taste/smell goes away with a longer steeping time when making a cafetière I’d try grinding your coffee slightly finer or using a smaller dose in the mocha pot. What are you putting in/getting out in grams?

 

[Brew_DD2]

Any rust spots anywhere on the inside of the water chamber?

 

[strange-steve]

You can get a sour profile if under-extracting espresso. Oils can also accumulate under seals etc and oxidise, giving a sour/bitter smell/flavour.

It sounds as though everything is nice and clean now, and given the taste/smell goes away with a longer steeping time when making a cafetière I’d try grinding your coffee slightly finer or using a smaller dose in the mocha pot. What are you putting in/getting out in grams?

I've tasted that sour/under extracted flavour when playing around with grind size but this was very different. Also I hadn't changed the grind recently, the flavour just came out of nowhere. Regarding grams, I'm not sure I just put enough in to fill the little basket without pressing it down, and fill the water chamber to just below the valve.

Any rust spots anywhere on the inside of the water chamber?

Nope, clean as a whistle.

 

[nixhaz]

I stopped using a stovetop one because of that exact flavour. The inside of the water chamber was all gnarly, as if it had corroded and I always thought that might have been the issue.

 

[Brew_DD2]

I stopped using a stovetop one because of that exact flavour. The inside of the water chamber was all gnarly, as if it had corroded and I always thought that might have been the issue.

I had the same with my last pot. It went when I bought a new one.

 

[strange-steve]

I stopped using a stovetop one because of that exact flavour. The inside of the water chamber was all gnarly, as if it had corroded and I always thought that might have been the issue.

It's a stainless steel pot rather than the usual aluminium ones and it looks like new, nothing obviously wrong with it. Anyway I've just got a new one, and am about to make a coffee in it so will report back...

 

[Session]

Weird! Really interested to see how the new pot compares

 

[nixhaz]

I ended up getting a Delonghi Dedica to replace mine. It's fantastic. you can vary the temperature and length of shot, plus it squeezes into a tiny spot. I love it so much I bought another one for work!

 

[strange-steve]

And the coffee from the new moka pot is perfect. Weird one.

 

[strange-steve]

I ended up getting a Delonghi Dedica to replace mine. It's fantastic. you can vary the temperature and length of shot, plus it squeezes into a tiny spot. I love it so much I bought another one for work!

That looks great but well outside my price range

 

[MyQul]

And the coffee from the new moka pot is perfect. Weird one.

So the old pot then. Glad you got it sussed. I love coffee (although I no longer drink it). I'd be well peed off If I was you and you couldnt find the source

 

[strange-steve]

So the old pot then. Glad you got it sussed. I love coffee (although I no longer drink it). I'd be well peed off If I was you and you couldnt find the source

Apparently so, I still can't explain what happened with it though

 

[nixhaz]

Yeah it's more expensive now than when I got it, IIRC it was £120 at the time in a sale. I'd spent more than that over the years on replacement stovetop ones/filters/seals so thought what the heck.

BTW have you replaced the seal and filter in the old one? I did and it helped for a bit...

 

[strange-steve]

BTW have you replaced the seal and filter in the old one? I did and it helped for a bit...

Actually I didn't and it's a couple of years old so very likely the problem.