cold trub removal before pitching.

[Kaiser]

Hi,

In the shows (and on his chiller page), I noticed that Jamil likes to emphazise the importance of cold trub removal from the wort that is pitched. I wonder why this is so important.

I believe one of the Papazian books states that the removal of all cold trub from the beer before fermentation will be detrimental to its flavor. It says that tastetests have shown that such a beer has an "empty" taste. I also found a reference to this subject on a German homebreweing board, where a well reputed member and brewer himself stated:

"The cold tub doesn not have an unsignificant effect on the taste of the beer. If removed completely before fermentation, an empty taste of the beer can be the result."

He also states that at least 30% of the cold trub should make it into the fermenter and that complete trub removal is not common anymore in German brewing.

Jamil,
have you tried your lager fermentations with or without cold trub and found taste differences? Also, are you removing all cold trub through whirlpooling? When I whirlpool after chilling and let it sit for 20min, I still have some cold trub in suspension, which makes it into the fermenter. Or are you removing the remaining trub after settling in the fermenter?

I just want to understand where the aguments for and against complete trub removal coming from.

Kai

[jamilz]

For lager fermentations, you need to remove the cold break.

It is IMPOSSIBLE to remove ALL of the cold break without getting the wort to near freezing and then filtering the wort. Yes, removing ALL of the cold break is a bad thing, mainly because it removes the nucleation sites and the CO2 builds up to a higher level.

Again, you would need to filter the wort to remove all of the cold break.

Fix had done some interesting tests on this very thing and determined that you want to remove the cold break. Me, I tried a few batches half and half from the same wort and decided the non-break batches were far cleaner and more stable.

[Kaiser]

Ok, that's what I thought. Most of the cold break should be removed, but some of it is needed for fermentation.

Once I brew 10 gal batches, I may try a side by side comparison too. But until then I try to leave most of the cold break in the brew kettle and don't worry about the stuff that is still in suspension as it is actually needed.

Thanks,
Kai

[jamilz]

Yes, exactly. A bit isn't going to kill your beer. Heck, a lot isn't going to kill your beer, but getting the majority out has a positive flavor impact on lagers.

As I recall hearing, George used to fill corney kegs with wort and then put them in an ice bath to create as much cold break as possible, then rack off of it and leave behind.

[Kaiser]

I definately have to do more reading on the subject. Recently I came across a paper that found that some of the break (in this case hot break was actually added to the fermenter) material actually contains nutrients for the yeast, which supports the idea that leaving some break material in the fermenter also affects the yeast in a positive way.

But then again there was, (and is), the use of settling tanks for removal of all break material before fermentation. It might be a debate similar to cold pitching vs. warm pitching, where both sides have their benefits and it its up to us brewers to understands these pros and cons and make our own decision based on that.

Kai

[jamilz]

The thing about the yeast synthesizing sterols from break material (is that what you read?) is that it is a last ditch effort for the yeast. If there isn't enough O2 for the yeast to start, and not enough cells to start, the yeast run out of the sterols needed to keep the cell walls pliant. They struggle fermenting and as they scrounge up the nutrients needed to keep going from the break material, this is where you see those slow, barely chugging along ferments. It happens, but it is far from ideal. And again, there is enough in there even when you cannot see any. If you see big chunks of break material in the fermenter, then that is more than you really need, even for this last ditch effort by the yeast.

[Kaiser]

here is the paper I was talking about: http://www.asbcnet.org/journal/pdfs/200 ... 4-0016.pdf

I acknowledge that the objective of this reserach was to find out wheter the lauter step and/or the whirlpooling can be shortrened in a commercial brewery. As a home brewer I'm not so much worried about that.

Kai

[jamilz]

That paper actually focuses on turbid lautering (with/without hot break) and doesn't have anything to do with cold break, which is what I thought we started talking about.

Even then, they admit the faster fermentation results in a large increase in 2-phenyl ethanol, which is a harsh, solvent alcohol taste that smells like roses or floral. I'll bet that is the "unpleasant bitterness" that the tasters mention. Certain alcohols can be bitter at a given level. I'm surprised they didn't make that connection.

All of that to save a few minutes on the lauter and whirlpool and one day of fermentation. Like you say, not very worthwhile for a homebrewer.