Question About Fermentation Time By Confused Beginner

[pokolbinguy]

4 degs should be ample. If you can leave it there for about a week then even better. This will let all the solids (yeast etc) in the beer drop to the bottom and you will end up with clearer beer.

 

[Scruffy]

That's fine mate - we're going through the processes, rather than getting too scientific (although I might...). 4 Deg C is a great starting point - about a week - taste the stuff while you go, get used to the changes...

These conditioning processes are yeast driven. The vigorous, primary stage is over, the majority of the wort sugars have been converted to alcohol, and a lot of the yeast are going dormant; but there is still yeast activity. During the earlier phases, many different compounds were produced by the yeast in addition to ethanol and CO2, e.g., acetaldehyde, esters, amino acids, ketones- diacetyl, pentanedione, dimethyl sulphide, etc. Once the easy food is gone, the yeast start re-processing these by-products. Diacetyl and pentanedione are two ketones that have buttery and honey-like flavours. These compounds are considered flaws when present in large amounts and can cause flavour stability problems during storage. Acetaldehyde is an aldehyde that has a pronounced green apple smell and taste. It is an intermediate compound in the production of ethanol. The yeast reduce these compounds during the later stages of fermentation.

The yeast also produce an array of fusel alcohols during primary fermentation in addition to ethanol. Fusels are higher molecular weight alcohols that often give harsh solvent-like tastes to beer. During secondary fermentation, the yeast convert these alcohols to more pleasant tasting fruity esters. Warmer temperatures encourage ester production.

Towards the end of secondary fermentation, the suspended yeast flocculates (settles out) and the beer clears. High molecular weight proteins also settle out during this stage. Tannin/phenol compounds will bind with the proteins and also settle out, greatly smoothing the taste of the beer. This process can be helped by chilling the beer, very similar to the lagering process. In the case of ales, this process is referred to as Cold Conditioning, and is a popular practice at most brewpubs and microbreweries. Cold conditioning for a week clears the beer with or without the use of finings. Fining agents, such as isinglass (fish bladders), Polyclar (plastic dust), and gelatin, are added to the fermenter to help speed the flocculation process and promote the settling of haze forming proteins and tannins. While much of the emphasis on using finings is to combat aesthetic chill haze, the real benefit of dropping those compounds is to improve the taste and stability of the beer.
That's where you're going, n'est pas?

Edit - spling rrr

 

[np1962]

Lately it seems we try to help the noobs with bits and pieces of information and end with disjointed threads that can be hard to follow.
There is plenty of info in the articles section or, as I did some time ago, you could read Palmers 'How to Brew'
Here is a LINK to the online version.
It is by no means the perfect resource but it is a good starting point.
Cheers
Nige

 

[The Big Burper]

Ok. So I'm a little bit confused by the cold conditioning part. How cold should I take the brew down to. I mentioned earlier that I have an old fridge I can use. I take it that around 4 degrees is what you mean?

Hi Fi,
4 will do, the colder the better. You will find after a week the beer will be as clear as.

I now do a secondary cooling in the fridge before I keg, as this stops the poor old dispensing fridge having hernia trying to get the 20 degree keg down to the set 6 degrees. And of course, the colder keg will absorb the CO2 faster.



cheers
BB

 

[manticle]

Recently my fridge has been taken up with a lagering pilsner so I've had to cc in a bath of iced water. Gets to about 8 degrees at its coolest and I leave the brew for approximately a week. It still seems to work so 4 should be fine.