LODO and copper chiller

[Eddievxx]

I have been trawling for info on lodo and would like to have this clarified. I found somewhere that washing off the oxide layer from copper coolers with StarSan would remove the problem for LODO. But is that the only oxygen ingress mechanism with copper?

[Owenbräu]

It's not an issue of oxygen ingress. The copper ions themselves turn dissolved oxygen into superoxide and make it highly reactive.

[Natebriscoe]

I have also been thinking about this, are we not pulling magnesium and copper from the malt during mashing? Then are those trace minerals not consumed by the yeast relatively quickly?

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[Techbrau]

Copper, iron, manganese, etc are mostly a concern at higher temperatures. Redox reaction speeds increase exponentially with increasing temperature. However, they will still catalyze staling reactions at colder temperatures, albeit at a much slower rate. So on the cold side, it is more of a question of how much are the metals going to accelerate the staling of the beer.

Yes, you are pulling trace amounts of iron and other metals from the malt during mashing. Sulfite will offer some protection from the Fenton super oxidizers. If brewtan B could bind up some of these metals, then I could see it working in conjunction with sulfite. There are many more naturally occuring compounds found in the mash and boil which are capable of chelating metals, and a lot of them actually end up in the break material. This can be a bad thing too, because the majority of zinc (an essential yeast nutrient) found in the malt gets trapped in break material and only a tiny fraction of the zinc from the malt ends up in the cast out wort. Of course, not all of the copper and iron are chelated either, and it takes as little as 10 ppb for them to catalyze the formation of superoxide.

Irish moss/whirlfloc/gelatin are all chelating agents as well. I haven't explored them much, though.

I'm not going to endorse using a copper chiller, but I would be less worried about a copper chiller than a copper brew kettle. Especially if your chiller is highly efficient and gets the wort cold fast. In cold wort the oxidation reactions are slowed down considerably.

[jonathan.dunphy]

Would it be better to rinse the copper chiller with starsan or a sodium metabisulfite solution 1oz/gallon
?

[Techbrau]

You are probably going to get leeching from the copper to one degree or another regardless of what you do. How big of a deal is that? Well, you can still make good beer with the low oxygen flavor even if you're using a copper chiller.

However, post-fermentation the main catalyzing agents for staling reactions are transition metals (iron, copper, and manganese are the most commonly found culprits in beer). The oxidizing enzymes found in malt such as lipoxygenase, polyphenol oxidase, peroxidase, and others are pretty much deactivated after the boil. So, expect your finished beer to stale faster the more metal you've got in it (source water is a big source of iron and copper, too). You can fight this by being even more careful about O2 pickup post-fermentation, because the metals still need a source of free oxygen in order to actually do damage.

[jonathan.dunphy]

Thanks techbrau.
I am curious about this due to my reluctance to scrap my current copper chiller setup as it cools down very very fast. I use a 50'x1/2" copper immersion chiller and a 50' copper counter flow chiller simultaneously. (They both get prechilled with a different 25' immersion in a cooler of ice water.).
The immersion chiller knocks the entire batch down to 40 c within 2 minutes. When the 40 degree C wort runs through the counter flow, it comes out at 14 C and I finish it off with an ice bath. So I'm at 14 C in 10 minutes and 6 C in 1.5 hours.
That being said, I noticed wine guys rinse bottles and racking equipment with a 1oz/gallon kmeta solution to combat oxygen during transfer. I've also noticed how shiny and new the copper chillers look after being submerged in stars san solution. Thanks for your thoughts. When I get a o2 meter I will try some experiments.

[Owenbräu]

A healthy fermentation is a great defense against copper downstream. That said, many people use a whirlpool addition of Brewtan B, which may also provide similar protection when using copper chillers.


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[Bryan R]

[Owenbräu]

Yeast can sequester metals.


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