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Discolouration in low wines after adding Sodium Hydroxide & heat.


I stripped a Birdwatcher recipe and added Sodium Hydroxide to the low wines to bring the pH to >12.

Then I attempted a spirits run in my T500, but it was misbehaving - I had dangerously forgotten to dilute the low wines from 70% back to 40%ABV.

When I inspected the wash (to dilute it back) it was obvious that the wash had changed from clear to a yellow/orange colour.
MOD EDIT : attached photo to forum ... don’t use external picture hosting
I diluted the wash back to 40%ABV but the colour didn't go away - suggesting that it isn't a titration but rather some kind of reaction - perhaps triggered from the heat from the still and concentration of congeners in a high ABV wash???

I've done this same neutral wash method a bunch of times before (without the mistake of not diluting) without seeing this discolouration effect. Anyone know what's going on?

As I replyed in your other post , you need to stop using Sodium Hydroxide .... its not needed and is causing issues .
viewtopic.php?f=16&t=29926#p7646492

I think you probably had a puke happening in this instance as well and most likely due to you not diluting back to 40% .The mix in the boiler would be very volatile .

You say you have done this NaOH stuff many times before .
I’m going to guess that all the orange stuff normally ends up in your boiler .

Yeah it was puking.

This is the first time I've seen the orange stuff. Third time I've used NaOH - previously used sodium carbonate three times as well.

Okay, found some more information on it - and it's worrying...

In the bottom of the pot there was some red/orange precipitate that had formed. The colour of the wash actually became clear again once it was allowed to settle.

I collected the precipitate - see images below (**not sure how to post the photos rather than links I'm sorry - tried researching it as well)
https://ibb.co/S5xgN8K
https://ibb.co/rxWHVVG

This reference (https://www.bbc.co.uk/bitesize/guides/z ... revision/3) recons that the sodium hydroxide may be reacting with iron nitrate in the wash to form iron III (Fe 3+). Not sure if there could be iron nitrate in the wash?

Any ideas if this is correct or where the iron nitrate may be coming from?