Cold break removal

[grs]

What's the general consensus on when to remove the cold break from ales in a cylindroconical fermenter? Just after the onset of fermentation? At the tail end of fermentation? When harvesting yeast?

What are the pros and cons of the timing?

grs

[beertje46]

Maybe Crassbrauer can give us the low down on the concept and use of the floatation tank for cold-break removal?

[mooneyray]

We blow cone after about +/-24 hours after the beginning of fermentation to take care of the cold-break.

I have floated chilled wort before....It worked but it was a pain. It's another tank to cip/sani, more CO2 usage, & another hour+ on your day, not to mention the increased potential for micro. problems.

[aswissbrewer]

I was just visiting the Brewing Trade Fair in Nürnberg and learned there that kettle finings are usful for exactly this purpose.
The finings are added to the boil, the wort is whirlpooled for the hot break and the finings go with the wort through the cooler, aerator and yeast dosage.
The cold break drops out with the finings at the start of fermentaion even though it isn't really all that cold.

The timing is important as the whole idea is to protect the yeast during its propagation phase.

At a previous workplace we used flotation tanks for lager beers. The wort (no finings) was cooled, aerated, the yeast added and pumped directly into the flotation tanks. The newly fermenting young beer was then pumped into the fermentation tank 16-20 h later. The cold break rises, due to the aeration, to the surface together with a lot of foam. As the beer is pumped out later the break sticks to the sides and is left in the flotation tank.

All very well, but we eventually stopped doing this as we were convinced it didn't help much - the yeast performed just as well, there was less work to do and the beer wasn't any the worse for not doing it.

[dick murton]

Most people don't worry about removing cold break as a separate operation providing the hot break and hops are removed OK. Kettle finings helps here. If you want to, the traditional UK operation has been to remove after about 24 hours, but the process tends to be rather wasteful of wort. It was often used as a means of getting air into oxygen hungry yeast as well, by literally dropping from one vessel into another. If using cylindroconical vessels, then discard the first few kilos / litres of mucky yeast, until it goes creamy white, then this yeast after this will probably be OK for pitching again.

[crassbrauer]

If you want to know about flotation, I copied this from a previous post:

Flotation is a practice which has been widely used throughout Germany and much of the brewing world to remove cold trub from the wort after cooling. High amounts of compressed air are used: between 30 and 60 liters of air per hl. The air serves two functions: it acts as a medium for transporting a portion of the cold trub (50 – 65 %) out in the foam and it aerates the wort. A high rate of yeast reproduction is the result. Why is it not detrimental to yeast reproduction? Because not enough oxygen dissolves in the wort for it to be toxic to the yeast at atmospheric pressure at the temperatures common at this stage in the brewing process. The excess air leaves as bubbles, which form dense foam which carries the cold trub out of the wort (cold trub particles are smaller than yeast; the yeast stay behind in the wort).


Additional information:

Cold trub (0,5 – 1,0 μm) contains short fatty acids, which are not good in the amounts (150 – 300 mg/l) present in the wort (the long fatty acids stay in the lauter tun). It's good to leave about a third in, when dealing with lager yeast. The yeast need it but if all the cold trub is left in, then the yeast can't be repitched as often. The German brewers who leave it in repitch their lager yeast about three times.

It appears that the excess oxygen compromises the anti-oxidative power of the packaged beer. There have, however, been no problems with yeast reproduction and repitching due to the large amounts of air used in the process. The wort contains 8 – 10 mg/l of oxygen after flotation.

I've also read that flotation tanks are no longer being built.

If they don't let it out the bottom of the CCF as Dick mentioned and don't practice flotation, then German brewers use a filter or a centrifuge.

[gitchegumee]

I've worked on a few systems with flotation tanks. The aerated wort was added through the top of the tall tank, and fell to the bottom of the tank to generate the foam. This foam was then cropped from the top of the tank. We called it a drop tank and it was used prior to pitching yeast.