Does Yeast protect the brew?

So, I'm wondering (due to the fact I've had a couple of spolied brews) does Yeast play any part in actually protecting and fighting against any possible infections that could be picked up in the Primary, or Secondary for that matter?

If the Yeast is old, or under used, could that make the brew more succeptible? Or does Yeast activity play no part in an infected batch?

Just curious.
J

No. Good sanitation combats infection. With good sanitation, you really never need to worry about any other defenses.

The only way a yeast plays a role is by dominating the wort. So, a good vigorous pitch and a big starter will give the yeast a jump start so they can outcompete most other beasties. Old yeast is less likely to take off, so you definitely want to make a starter.

But it's not a solution. Some bacteria can exist right alongside ale yeast.

Really, sanitation is the name of the game.

jaymack said:

So, I'm wondering (due to the fact I've had a couple of spolied brews) does Yeast play any part in actually protecting and fighting against any possible infections that could be picked up in the Primary, or Secondary for that matter?

If the Yeast is old, or under used, could that make the brew more succeptible? Or does Yeast activity play no part in an infected batch?

Just curious.
J

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The yeast itself does not protect the brew. But fermentation raises acidity and alcohol level in your wort as it becomes beer. Most bacterias and other germs don't thrive well in this environment. But as Janx pointed out, a few can.

In general, the higher the ABV and the higer hopped the beer is the less likely it will be spoiled.

Kai

I agree with Janx. Sanitation, sanitation, sanitation. once the yeast gets going good and strong, the chances of infection are reduced, but the nasties can and do get in at any time.

Did you find the source of the infections? And are you sure it was infected and just not the flavor you were looking for? What are you using for cleaning and sanitizing?
If the yeast is old and has been reused a number of times then it can pick up off flavors as the yeast mutates. This could make your brew taste "off".

Booboo;

I use a dash of bleach for sanitation and follow with a boiled-water rinse.

My most recent stout has got the caramely-diacetyl like scent and taste. From what I've read, I understand that this "taste" can be normal for some english ales, but this sense/taste is more so than what I would believe to be deemed normal.

My Pale Ale I've got in the Primary now was my first batch with SO MUCH yeast activity (bubbles, foam, and gushing, oh my:cross: ) that I posted my original question, in the hopes that perhaps this will assist in helping my brew go south.

Cheers,
J

Yep, I agree with all of the above, if the yeast are heavily outnumbered by "bad bacteria", they won't stand a chance. Santitise the battlefield, and they will have a much better fighting chance. Lots of hops also help to provide an "antispetic" environment (hence IPA's being traditionally heavily hopped for the long journey east to India...but that's another story).

jaymack said:

Booboo;

I use a dash of bleach for sanitation and follow with a boiled-water rinse.

My most recent stout has got the caramely-diacetyl like scent and taste. From what I've read, I understand that this "taste" can be normal for some english ales, but this sense/taste is more so than what I would believe to be deemed normal.
J

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Rince well with the boiled water to remove any bleach smells and residue. I recommend using a no rince sanitizer like Star-san which can be ordered here http://www.paddockwood.com/index.php . You could be either scorching your wort in the kettle or you could be using out of date extract. Some good reading can be found here http://www.howtobrew.com/ if you are interested.
Cheers. BTW did you feel that earthquake last night? Some fellow club members in Ottawa said it was like a train went through their house.