hot side oxidation??
- Thread starter robsan77
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Im definatley on the side of it being real. Some of the best improvements to my beers have come from changes in my processes that eliminate splashing - the obvious source of oxygen - and hence HSO.
There's loads written on this subject already in the brewing literature. The contentious thing with HSE is that is takes a while to present itself as a problem. There is no obvious way of knowing whether your wort has picked up too much oxygen when hot when you are making it and the results take at least a few weeks to show. Its best to assume that any contact between hot wort and air is detrimental, and do anything to avoid it. Come to think of it, the commercial breweries I have seen (all two of them :grin: ) have systems where the wort is cooled down quickly after boiling, without it ever touching air (all via plate heat exchangers). Im sure there is a very good reason for this, as copper coils in wort also work well, but rely on continued exposure of the wort to air while they are working, but (!) are a lot cheaper to make, easier to use, and easier to maintain.
I was just reading a book on this the other day (Principles of Brewing Science, G. F. Fix, 1999) and in it, he reported something that i thought was important, that exposure of hot wort to air sets off chemical reactions that consume the absorbed oxygen (1mL of oxygen in wort at 70 oC is gone in seconds apparently) and produces secondary compounds that eventually lead to nasty tasting things (the dreaded trans-2-nonenal being one, the compound responsible for papery/cardboard flavours). Given that hot wort cant absorb much gas anyway (hot liquids generally dont), you can say that there are some very vigorous oxidation processes at work in hot wort, that are just waiting to pounce given the chance.
There are a few other issues (like how dark the beer is) which muddy the issue somewhat, as darker beers are less prone to this that lighter beers, on the grounds of their higher melanoidin content (which provides a protective effect) is higher.
I think at the end of the day, if you have tasty beer, then u are winning :
wahoo! :thumb:
There's loads written on this subject already in the brewing literature. The contentious thing with HSE is that is takes a while to present itself as a problem. There is no obvious way of knowing whether your wort has picked up too much oxygen when hot when you are making it and the results take at least a few weeks to show. Its best to assume that any contact between hot wort and air is detrimental, and do anything to avoid it. Come to think of it, the commercial breweries I have seen (all two of them :grin: ) have systems where the wort is cooled down quickly after boiling, without it ever touching air (all via plate heat exchangers). Im sure there is a very good reason for this, as copper coils in wort also work well, but rely on continued exposure of the wort to air while they are working, but (!) are a lot cheaper to make, easier to use, and easier to maintain.
I was just reading a book on this the other day (Principles of Brewing Science, G. F. Fix, 1999) and in it, he reported something that i thought was important, that exposure of hot wort to air sets off chemical reactions that consume the absorbed oxygen (1mL of oxygen in wort at 70 oC is gone in seconds apparently) and produces secondary compounds that eventually lead to nasty tasting things (the dreaded trans-2-nonenal being one, the compound responsible for papery/cardboard flavours). Given that hot wort cant absorb much gas anyway (hot liquids generally dont), you can say that there are some very vigorous oxidation processes at work in hot wort, that are just waiting to pounce given the chance.
There are a few other issues (like how dark the beer is) which muddy the issue somewhat, as darker beers are less prone to this that lighter beers, on the grounds of their higher melanoidin content (which provides a protective effect) is higher.
I think at the end of the day, if you have tasty beer, then u are winning :
wahoo! :thumb:
Nice post Paul!
It's an interesting topic, especially as it's so important to get oxygen into the wort immediately after chilling and before adding the yeast.
I'm still unsure but I work on the principle that minimising the exposure to air isn't really that difficult usually, so best be on the safe side!
It's an interesting topic, especially as it's so important to get oxygen into the wort immediately after chilling and before adding the yeast.
I'm still unsure but I work on the principle that minimising the exposure to air isn't really that difficult usually, so best be on the safe side!
It is a very real phenomenon BUT in the UK it is extremely unlikely that we will experience it with our malts and beer styles and brewing techniques.
I have gone on about it ad nauseam (And Here)
I have gone on about it ad nauseam (And Here)
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