Lager questions for bottling.

[GilSwillBasementBrews]

Gravity Before Boil: 1.048 SG (12.7 Brix)
Original Gravity: 1.056 SG (14.8 Brix)
Final Gravity: 1.017 SG (8.4 Brix)
Volume Before Boil: 6.75 US gals
Volume After Boil: 5.75 US gals
Volume Transferred: 5.50 US gals
Volume At Pitching: 5.50 US gals
Volume Of Finished Beer: 5.00 US gals
Total Water Required: 8 US gals
Preparation
Heat 4 US gals of water to 171 F.
Mashing
3lb LightMunich Malt
3lb Dark Munich Malt
2lb 4oz Vienna Malt
2lb Pilsen Malt
Allow the temperature to stabilize at 156 F. Allow to rest at this temperature for 60 minutes.
Vorlauf and drain
Add 2 US gals of water at 170 F, mix and run off.
Add a further 2 US gals of water at 170 F and mix.
Run off to collect a total of 6.75 US gals of wort
Bring the wort to the boil.
Add the following hops at the times given.
1.00 oz of German Tettnang (60 Min From End)(alpha 3.7%)
1.00 oz of German Tettnang (15 Min From End (alpha 3.7%)
1.00 oz of German Hallertauer Mittlefruh (5 Min From End)(alpha 4.3%)
Boil 60 minutes
Pitched
WLP820-Oktoberfest/marzen
Brewed 2/9/13
Fermented 52F
Started lagering 2/18/13 @42F.

So now the usual questions.
How long should I lager this beer for?
Should I add yeast at bottling time?
Thanks in advance for any recommendations.

 

[daksin]

1 week per 8pts OG, so that gives you 7 weeks. Lagering should be done much colder than you have it, though, at or near 33F. You won't see much benefit from lagering warmer, as you won't get the polyphenols and other undersirables becoming insoluble and dropping out at those temperatures. Yeast may drop out more, but that's not really what lagering's for. After 7 weeks at lager temps, I would add some yeast back to bottle.

 

[GilSwillBasementBrews]

Thanks daskin I did have the temp around 1C but once the top inch or two started to freeze I got worried and turned the temp up. Being my first lager I really don't know what I should be expecting. Is it OK for the beer if the top bit of it turns to ice?

 

[Yooper]

At 1 C, the beer won't freeze, so I suspect your thermometer is wrong.

You don't want the beer to freeze, and it will freeze at about -2.5.

So keep it just about freezing, or at 1C. If your beer is freezing, the temperature is obviously lower than 1C, so raise it a bit.

 

[GilSwillBasementBrews]

At 1 C, the beer won't freeze, so I suspect your thermometer is wrong.

You don't want the beer to freeze, and it will freeze at about -2.5.

So keep it just about freezing, or at 1C. If your beer is freezing, the temperature is obviously lower than 1C, so raise it a bit.

Thanks Yooper.
I'm not certain how accurate the temp is. To be honest I didn't check it with an actual thermometer. I'm using the temp probe for the STC-1000 and have the sensor taped to the side of my LBK at just below the surface of the beer. So I will lower the temp back closer to 1C and bump it up a few .1's until the surface isn't freezing.