Weird shit upsizing

[The Beast of Bodmin]

Anyone had any issues upsizing?

I have had great success with a chosen recipe however, whenever I try to upscale it (from 25L to 75) I keep getting an awful plastic type taste that is causing a trip down the sink. I'm not doing anything different apart from using different size vessels, well cleaned and sanitised, and am even running the temp sensor in the fermenter to ensure that things aren't getting too warm.

My first thought was that the temp was causing yeast issues but I've now eliminated that problem.

Driving me mad as this brew at small volumes is outstanding, as soon as I upsize it all goes to rat-shit.

 

[MHB]

Most common cause of a plastic flavour is plastic, what is your new fermenter, if its a cheap plastic it may be giving off plasticiser (chemicals added to plastic to make them flexible).
Getting the heat out of a larger fermenter is a lot harder than a small one, if you play around with the volume : surface area relationship, you will find that the larger fermenter has a lot less surface to shed heat. It is possible that the bottom of the fermenter is a lot hotter than you would expect and you could be getting a lot of yeast autolyses.
I don't know how many times I have suggested putting a fan in a fridge but again, its a really good idea, dramatically improves the consistency and efficiency of your temperature control.
Mark

 

[The Beast of Bodmin]

Thanks for the quick response.

My fermenter is made out of food grade plastic and also my brew buddy is using the same fermenter without the same problem (he's having other issues but more related to consistency). I did also make a big effort to ensure that the wort was cool enough, or so I thought, prior to pitching yeast on the last occasion and putting the sensor into the wort directly I was expecting a much more predictable result. Pretty gutted when this one has turned out lousy. As I said before, I'm hitting the spot on small volumes but missing by miles as soon as I upscale it.

Guess I'll leave a bit longer before pitching to ensure that my wort is right down in temp

 

[The Beast of Bodmin]

The other problem I am considering is water quality. It's a bit variable where I am and I did start using purified water but didn't on the last batch.

 

[MHB]

Boil a jug of water, pour the boiling water into your fermenter, let it cool over night, smell/taste the cooled water, if it stinks/tastes of plastic that will give you a good starting point.
Not all plastic are made equal - its worth checking.
Mark

 

[Adr_0]

If you've changed water, have you dechlorinated the water you now use?

Any thread sealants lurking around on your kettle that won't appreciate hot temps?

 

[klangers]

Is your brew rig the same for both batch sizes?

 

[mr_wibble]

I had a similar problem in previous batch.

I think my cause was that the wort wasn't getting as cool as I thought (it was still in the 30s),
so I was pitching way to warm. This was directly caused by running the hot wort through the plate chiller too fast.
(and the tank-water temperature might be a bit higher in mid-summer).

I wouldn't say the taste was "plasticy" though, more "twangy" ... I guess this could be kind of the same.

 

[Danwood]

As ADR mentioned above, chlorine/chloramine levels can contribute to plasticy phenol off-flavours. I think these would be more noticeable in lighter coloured styles aswell.
But you say it only happens when you upscale with the same water source. Logically, it is probably from an actual plastic contaminant then.

 

[jaypes]

I have had this before, was traced to the garden hose I was using for larger batches

 

[Danscraftbeer]

I got it a few times too. I concluded it was plastic fermenters that had done too many miles. I fixed the best one and retired the old ones to vinegar making (another brewing journey).
I fixed the good ones by filling them with boiling water with the correct measured and dissolved amount of Sodium percarbonate. Tossed in the O ring seal and fitted the lid so its completely in contact with all inside surface. Left them overnight and repetitively rinsed thoroughly with more boiled water until there was no detectable smell of old beer or plastic. Not an easy fix (especially for a 100lt fermenter or whatever you have but it worked.
I also bought a Kegmenter for larger brews. You can literally boil the crap out of it. No residual smells or flavours from Stainless Steel.

 

[bradsbrew]

How is the yeast health when pitching, are you doing anything different there?

 

[The Beast of Bodmin]

Ok lots to look at there, here's some more detail on my system.

1. Fermenter is identical to my brew buddy's so struggling to see that as being the issue but will try the boiled kettle to see if there is a discernible difference.
2. No sealants at all are used wherever possible in my system. I am paranoid about plastics leaching in and the only element of my system that is plastic is the fermenter. (could be that but see above)
3. I haven't treated the water which I guess is why I'm thinking in that direction. Water is really the only big change. Last few brews were with purified water. At 30c a litre it gets expensive over a big batch but putting beer down the sink pisses me off more.
4. Hoses and washers that I use are all silicon and very well sterilised before use.
5. I am running the temp sensor in the wort (well cleaned and sterilised) to keep more accurate control on wort temps during fermentation. Temp sensor controls the fridge. I also have a second sensor in the fridge sending to a readout so I can compare the two temps. This is definitely showing the exothermic reaction but the controller is coping and maintaining wort at the right temp. (19 deg for my beer).
6. Fermenter has only done three or four batches so far.
7. I run an all copper counter flow chiller (took lots of effort to build) and there is no possibility of cooling water getting to my precious wort.
8. My yeast starters are like mount vesuvius prior to pitching after spending 24 hrs on the stir plate in my fermenting fridge to match starter temp to wort temp. Wyeast 1469
9. Using a 100L fermenter but only brewing 75L batches to leave sufficient head space.

My two suspects are yeast or water. I'm leaning towards water as I have been very careful with yeast having had previous disasters. Whenever I brew 25L batches I have no issues at all (but using purified water) as soon as I go 75L all goes to rat shit.

 

[MHB]

You can get two cars of the same production line, one runs like a Swiss watch and the other is a lemon. You would be ill advised to take the notion that your mate isn't having the same problem as any sort of proof.
Stop saying what it cant be, and look at what is really happening. Any other method of problem solving makes it harder not easier, start at the beginning of your process, identify every step and the equipment associated with that step. Pay particular attention to equipment unique to the larger batch. Smell and taste each piece of equipment. smell and taste you yeast starter and your water.
On the water, for tap water to make tippable beer it would pretty much have to be undrinkable water, I would suspect only extreme chlorine could make that much difference and we are talking swimming pool not tap water.

Preserver
Mark

 

[TheWiggman]

Some infections can also cause plastic-like flavours. Might be a coincidence, might not. If the fermenter is identical identical to your mate's why not swap it and rule that out?