recognise this infection? craters on yeast cake

I've started losing batches to a strange infection. Beer tastes pretty good towards the end of fermentation, but flavour is slowly stripped to leave a turbid, bland, unfresh tasting beer by the time it is kegged. This same pattern is evident. Only visual sign apart from the turbidity is the strange formation of the yeast cake in the fermenter. Yeast captured from the batch also forms these craters/bubbles.

Any idea what it is? I'm very thorough with sanitation, so its got to be a tough bug, or maybe something airborne.

Ive attached the pic link, but its not coming up for some reason.

The "craters" are quite possibly just co2 escaping, I've seen this, but it's hard to tell without a pic.

Did you do this:

Keep on brewing my friends

Craters in the yeast cake is normal as stated above. (If it looks like I think it does) Infections usually show themselves on the surface, or in the beer itself.

I think the pic should be this one:

Good looking, healthy yeast cake doing it's job!

foles said:

Ive attached the pic link, but its not coming up for some reason.

Click to expand...

the reason the pic isn't showing up for you is that you are linking to the flickr page that contains the image (http://www.flickr.com/photos/90714604@N00/4796216582/in/photostream/) instead of the image itself ->
http://farm5.static.flickr.com/4073/4796216582_dd198d31f2.jpg
:rockin:

My yeast cakes almost always look like the surface of the moon after I rack the beer of 'em. I consider it a sign I was successful in racking all the beer off without disturbing the cake. It's just what's left behind when a big bubble of CO2 works it's way out of the cake.

looks like bubbling yeast to me. the escaping CO2 made some CO2 volcanos. thats what it looks like to me.

foles said:

I've started losing batches to a strange infection. Beer tastes pretty good towards the end of fermentation, but flavour is slowly stripped to leave a turbid, bland, unfresh tasting beer by the time it is kegged.

Click to expand...

That does not sound like an infection. That sounds like oxidation.

Cpt_Kirks said:

That does not sound like an infection. That sounds like oxidation.

Click to expand...

Interesting....

Even without the sherry taste? I've tasted oxidised beers and it doesnt seem the same? But maybe an early oxidation tastes a bit different?

I've recently been using my silicon tube for racking into the keg - its a bit larger dia than than I should be using, so maybe its splashing the wort a lot more. But it seems to be turning before that stage. That leaves HSA (surely not)?