Lagering - What is actually happening in my fridge?

[J_P]

Sorry if this sounds a bit thick but I'm just wondering what lagering lager actually does.

The stuff in my fridge tastes crystal clean after racking (14 days primary) except for the extremely faint splash of diacetyl that Aleman informed me I could expect with WLP830, and you really have to go looking to find that.

How is 12 weeks in the fridge going to make it better?

Answers on a postcard please :

 

[steve_flack]

Did you do a diacetyl rest?

 

[mysterio]

Clarifying, along with the precipitation of polyphenols, makes for an overall crisper beer but lagers can taste great after fermentation if they're brewed well. 12 weeks is overkill IMO (unless it's a bock or something), you should notice a difference after 3 or 4 weeks lagering, although it should continue to improve... to a point.

The diacetyl should really be nearly imperceptible, if you give it to someone to drink and they comment on any butter flavour, or if you can smell it, then i'd say it's a flaw. Is that the PU yeast?

 

[J_P]

Did you do a diacetyl rest?

I raised it to 15C for a couple of days at the end of the fermentation

Is that the PU yeast

According to Mr Malty it's a Wiehenstephan strain of some description. The diacetyl is extremely faint could I be getting it mixed up with the flavours from the Vienna and Melanoidin malts I used in it?

 

[delboy]

I find there is a grainy taste to lagers when first fermented, which fades after a few weeks lagering. I suppose in an ordinary beer this slight grainyness is a part of the flavour or hides in behind the other malts and hops.

 

[Aleman]

Diacetyl is a flavour component of Bohemian pilsners, and helps to 'tame' the high hop rates used. . . . If it is identifiable as diacetyl then it should be considered a flaw . . . the ideal level is just below the taste threshold . . . sounds as though you have got it pretty much spot on.

Mysti is right although it looks clear, and tastes clean, further precipitation of polyphenols will take place which will 'improve' the flavour.

The 12 weeks come from the old Plzen rule for each degree Plato 1 hour mash, 1 day primary fermentation and 1 week lagering . . . so a 12 Plato beer (1.048) would have 12 weeks lagering . . . I normally go with 4-6 weeks . . . but two of those will be at -1 to -2C