Permanent Off Taste

[Harto]

Hi All,

When doing AG homebrew I'm getting an off taste every brew. I'm not really able to put the taste into words. It's not undrinkable (ie totally disgusting) but it's bad enough that I would take it back in a pub. Very strong taste and smell. Best way I can describe it is tangy and sour.

I've been racking my brain to think of how this taste could be getting in and I've come up with the following
- I don't condition the water in any way. However I do a full 60 minute boil and my local water tastes pretty good
- The mash tun has 2 stainless steel jubilee clips inside. They've gone a dull grey rather than shiny but I sucked one of them just to try and there was no particular off taste
- I sparge by pouring a litre of water at a time into the mash tun whilst drawing off the wart. However because my mash tun is an old cool box it loses heat quickly so my sparge water is often near boiling to keep the temp up, especially near the end of the mash when it is at its coolest. I have on occasions put a boiled kettle of water in or three if I've run out of water from the HLT. I stir the top of the grain to even out the temperature and once I stir the water quickly goes down below 70oC. Could this practice be extracting off flavours?
- I use a copper coil wart chiller. It goes in for the last 15 minutes of the boil. It goes in dull and always comes out shiny. Could this impart any off flavours?

I think my cleaning/ sanitation is pretty good. I clean with soda crystals and oxy and sanitise with Starsan although I spray and swish over a long period rather than soaking.

Any thoughts? Any help would be much appreciated- I'm not far from giving up!

 

[MyQul]

Sour taste immediate makes me think infection. If it's some sort of wild yeast infection rather than bacteria, star san wont touch it as it only deals with bacteria. Time for the nuclear option - bleach. 120ml (thin, the stuff you get for 17p for 2L not domestos) bleach/2L is a strong solution, soaked for 20 mins will kill wild yeast - if thats what it is (bleach will kill bacteria too of course

 

[Covrich]

Sounds like possibly wild yeast infection.. what is your finishing gravity on these beers and do they seem over carbed?

 

[Dads_Ale]

Here are some of my initial thoughts.

I have always boiled my mash water for 15mins adding a Camden tablet and 1tsp citric acid. Then I let it cool to the desired temp for mashing. This regime may need to be tweeked depending on the water in your area. I just guessed at mine but it seems to work for me. Do you take a PH reading of the mash at the start?

You sparge water is too high. You need to make sure the grain bed does not exceed 77c so as not to extract excess tannins. Could also be over sparging, the last runnings should not go below 1005 ( I have also seen 1010 quoted as the cut off point). Be mindful of the wort temp if taking gravity reading at this point and adjust the reading accordingly. I never worry about what the actual grain bed temp is during sparging (the flow effect seems to give a false low reading), but rather make sure the sparge water is not too hot.
You may need to look at replacing or lagging your mash tun in order to reduce the amount of heat loss

Lots of people use copper immersion chillers without any issues.

One final point is some sort of contamination or wild yeast infection. You may be wise to replace your FV (if it is plastic). The pre-boil equipment you could deep sanitise with VWP (rinse well with cold water).
I tend to clean everything with PBW after each brew and then sanitise on the day with a Starsan Spray. I find PBW is really good at getting rid of the residual crud (better than VWP in fact but VWP does sterilise as well)

Hope this helps

Hopefully the above helps

 

[TheRedDarren]

+1 on all that has been said.
I'd check your fv for scratches which may harbour bacteria.
As MyQul says, it's nuclear time, but I may be tempted to ditch old plastics and replace.

 

[Harto]

Thanks for all your thoughts. Regarding the FV, I've only done half a dozen brews from new, 5 at AG and everyone of them had the same problem. Does this sound like the problem? Also, I kept a sample pre - ferment. It had a funny taste, not quite the same or as strong as post ferment but maybe the makings of that taste when amplified by fermentation?

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[Vinnyc]

What temp are you fermenting at? Also what temp control during fermentation

 

[Harto]

17.5 in a brew fridge controlled by stc1000

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[Richie_asg1]

If the bleach method doesn't work then I would replace your mash tun.

Old plastics - used for coolers and ice boxes seem to age particularly badly and can leech plasticisers. If you suspect it may be this, try a few pints of fresh boiled water into it when cleaned as per normal, and after a few hours see if there is any taste to the cooled water.
If it tastes clean - then go looking for another reason.

 

[Harto]

This is all great advice thanks guys. One question is should I use the bleach neat or water down with boiled water?

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[MyQul]

If the bleach method doesn't work then I would replace your mash tun.

Old plastics - used for coolers and ice boxes seem to age particularly badly and can leech plasticisers. If you suspect it may be this, try a few pints of fresh boiled water into it when cleaned as per normal, and after a few hours see if there is any taste to the cooled water.
If it tastes clean - then go looking for another reason.

What are plasticisers?

 

[Richie_asg1]

What are plasticisers?

It's what makes some types of plastic more flexible. They are an additive to the main polymer to do things like improve flow in the moulding process and make the finish product resist cracking.
The problem is that over time they leech out, and this is made worse with heat. You may actually feel them if you handle old PVC picnic plates that after long storage suddenly feel greasy.
As they come out the plastic ends up brittle and liable to crack. There was a big thing about them a few years ago when non-pvc cling film came out as it was proven that heating greasy food in PVC film caused the plasticisers to migrate into the food. :nono:

So it is possible heating water inside plastic containers may allow an off taste to come from the plastic itself. It can also allow oils that may have migrated into the plastic in the past to come back out too. For example if the cooler had been used to store fish at any time in the past.