When is beer most vulnerable to contamination?

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cnoyes

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I'm wondering at what points is beer the most susceptible to contamination from bacteria or mold infection.

For example, I'm guessing that it isn't very vulnerable if you're racking to a keg and putting it straight into the fridge.

Anybody have any better knowledge on this than me?
 
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cnoyes

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Yuri_Rage said:
Read all about it in the first chapters of www.howtobrew.com.
There's a lot there about how to sanitize and how important it is, but I'm not seeing anything relevant to my question. Could you be more specific?
 

mrkristofo

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Immediately after the boil, before pitching the yeast, once the temperature is below about 150˚F.

But as Yuri mentioned, have a good read of Palmer's book.
 
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My answer is a not so subtle prod to try searching and reading before asking for help. Your question is so basic, it indicates you have done neither.
 
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cnoyes

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Yuri_Rage said:
My answer is a not so subtle prod to try searching and reading before asking for help. Your question is so basic, it indicates you have done neither.
Perhaps my question wasn't clear. I am not interested in when I should be concerned with sanitation. I know the answer to that. I am curious about the biological and chemical process, and how a bacterial or mold infection occurs in that respect. Does the CO2 found after primary fermentation has begun inhibit bacterial growth? Is the beer particularly vulnerable when you rack it to secondary? Does the refrigeration when you put it in a keg help to guard against bacterial growth? Etc.

I have read all of howtobrew.com. I know how to do a search. If you're going to be so condescending in the future, don't bother replying. Especially if you don't have any relevant information.
 

DuPuma

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Yuri_Rage said:
My answer is a not so subtle prod to try searching and reading before asking for help. Your question is so basic, it indicates you have done neither.
Cut him some slack... this is a message board, not a research database. Sure, he could spend an hour or so searching around and maybe find the specific answer he's looking for. Or maybe not. Either way, a forum is the exact kind of place to post questions, even those that have been answered previously.

I'm sure he appreciates links to helpful information, but give him a break.
 

SuperiorBrew

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cnoyes said:
Perhaps my question wasn't clear. I am not interested in when I should be concerned with sanitation. I know the answer to that. I am curious about the biological and chemical process, and how a bacterial or mold infection occurs in that respect. Does the CO2 found after primary fermentation has begun inhibit bacterial growth? Is the beer particularly vulnerable when you rack it to secondary? Does the refrigeration when you put it in a keg help to guard against bacterial growth? Etc.

I have read all of howtobrew.com. I know how to do a search. If you're going to be so condescending in the future, don't bother replying. Especially if you don't have any relevant information.
Chapter 7 - Boiling and Cooling

7.4 Cooling the Wort

At the end of the boil, it is important to cool the wort quickly. While it is still hot, (above 140°F) bacteria and wild yeasts are inhibited.

The hotter the wort the more susceptible to contamination you are. Thats what everyone was telling you. You will find this info in any brewing book or website, plus it is really just common sense.
 

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SuperiorBrew said:
At the end of the boil, it is important to cool the wort quickly. While it is still hot, (above 140°F) bacteria and wild yeasts are inhibited.

The hotter the wort the more susceptible to contamination you are. Thats what everyone was telling you. You will find this info in any brewing book or website, plus it is really just common sense.
Aren't the bold statements contradictory?
 

SuperiorBrew

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9/9 said:
Aren't the bold statements contradictory?
I respectfully retract my hasty post due to too many Apflweins :drunk: & I'm going to bed now
 

david_the_greek

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I've always worried about contaminating my wort. I figured right after the boil, during cooling. But, after thinking (no I didn't hurt myself in the process :) ), hot air is still rising out of the bucket/pot until its fairly cool. This should help keep airborne particles from falling into the wort since it has hot air rising off of it. This theory works for smaller vessels slightly better but I think the principle still applies. So from that stand point your only risk is stirring with a dirty spoon or drooling as you smell that amazing aroma. Another potential hot spot I would think is the hydrometer sampling. Though as long as you sanitize your thief or hydrometer you shouldn't get any contamination. There is the risk that airborne bacteria or fungi could get into the fermenting wort though promptness ensures that the exposure time is minimal. Also once things are fermenting along, the yeasts are the big fish of the pond. They've eaten a lot of the available resources and hopefully have made it hard for much competition.
 
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WOW I have been gone for some time and I now see why!!!! I think I understand your question and am willing to give you my .02 without making you feel like a jacka$$ for asking. As you know once you get below aprox 150 your at risk BUT... as your wort turns into beer and you produce alcohol the alcohol will assist in fighting off bacteria its not enough to rely on it altogether. after your wort is beer and its finished your biggest killer is going to be light, heat and oxygen. If during your transfers you make sure your kegs are sanatized and you keep the oxygen away your golden. I hope that helps.
JJ
 
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cnoyes said:
Perhaps my question wasn't clear.
No, it wasn't. We routinely have the same conversations over and over here at HBT, and the answers to most simple questions are already here. The phrasing of your first post made it seem as if you were too lazy to use Google, a book, or any number of other means to answer your question. It's hard to help someone who isn't interested in helping himself (in this case, not you). Perhaps I was a bit harsh, and for that, I do apologize.
cnoyes said:
I am not interested in when I should be concerned with sanitation. I know the answer to that. I am curious about the biological and chemical process, and how a bacterial or mold infection occurs in that respect. Does the CO2 found after primary fermentation has begun inhibit bacterial growth? Is the beer particularly vulnerable when you rack it to secondary? Does the refrigeration when you put it in a keg help to guard against bacterial growth?
Ok, this is a much better jumping off point for discussion!

Once the yeast has taken hold and begins to reproduce and subsequently ferment, it tends to act as a natural "immune system" for the beer. The colony's activity tends to overwhelm any bacteria or wild yeast that come in contact with the beer. Then, as CO2 and alcohol are produced, the environment inside the fermenter becomes even less hospitable for infectious organisms, especially aerobic bacteria and mold. The combination of active yeast, CO2, alcohol, and hop compounds make beer rather resilient in fighting off foreign bodies.

Once the beer is completely fermented, it is far less susceptible to infection than when it existed as warm, sugary wort. There isn't much left for bacteria, wild yeast, and mold to "eat," and the alcohol content is relatively high compared to most substances found naturally, so an infection is even less likely than when fermentation was active. Assuming a relatively clean environment, the biggest threat to your beer when racking to secondary or to a keg is oxidation. A careful, clean, no-splash transfer will minimize the risk of both oxidation and infection.

After a keg or bottle is sealed, there is no way for an infection to take hold. If one was pre-existing, refrigeration will slow its progress, but there isn't much that can be done to stop it. Cool, stable temperatures will help preserve a beer's character, but there is no risk of additional infection after bottling or kegging.

So, indeed, in terms of infection, the riskiest part of brewing is during that time when the wort is warm (not hot), and fermentation activity has yet to begin.
 
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cnoyes

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david_the_greek said:
So from that stand point your only risk is stirring with a dirty spoon or drooling as you smell that amazing aroma.
Ha, drool.

I disagree with you, though. I don't particularly enjoy the aroma until it's been fermenting. However, I do like the smell of the mash.
 
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cnoyes

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Yuri_Rage said:
No, it wasn't. We routinely have the same conversations over and over here at HBT, and the answers to most simple questions are already here. The phrasing of your first post made it seem as if you were too lazy to use Google, a book, or any number of other means to answer your question. It's hard to help someone who isn't interested in helping himself (in this case, not you). Perhaps I was a bit harsh, and for that, I do apologize.

Ok, this is a much better jumping off point for discussion!

Once the yeast has taken hold and begins to reproduce and subsequently ferment, it tends to act as a natural "immune system" for the beer. The colony's activity tends to overwhelm any bacteria or wild yeast that come in contact with the beer. Then, as CO2 and alcohol are produced, the environment inside the fermenter becomes even less hospitable for infectious organisms, especially aerobic bacteria and mold. The combination of active yeast, CO2, alcohol, and hop compounds make beer rather resilient in fighting off foreign bodies.

Once the beer is completely fermented, it is far less susceptible to infection than when it existed as warm, sugary wort. There isn't much left for bacteria, wild yeast, and mold to "eat," and the alcohol content is relatively high compared to most substances found naturally, so an infection is even less likely than when fermentation was active. Assuming a relatively clean environment, the biggest threat to your beer when racking to secondary or to a keg is oxidation. A careful, clean, no-splash transfer will minimize the risk of both oxidation and infection.

After a keg or bottle is sealed, there is no way for an infection to take hold. If one was pre-existing, refrigeration will slow its progress, but there isn't much that can be done to stop it. Cool, stable temperatures will help preserve a beer's character, but there is no risk of additional infection after bottling or kegging.

So, indeed, in terms of infection, the riskiest part of brewing is during that time when the wort is warm (not hot), and fermentation activity has yet to begin.
There we go. Thanks for the reply. Sorry I wasn't clear initially.
 
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