Dry Hopping and cold crashing

[JonD_87]

Hello. I used to be quite into my all grain brewing, but children and life got in the way! However, I'm back into the brewing as of last weekend. I found an old fridge on Facebook, converted it into a brew fridge and started with a Sierra Nevada clone.

I just wanted to clarify a couple of things as I have never had a brew fridge before and I am a bit rusty (been about 4 years since my last brew!)

I haven't had any bubbles coming through the airlock, but the headspace is quite small in the fridge and I have had to angle the airlock to squeeze it in. The smell is very familiar so I am sure something is going on, perhaps the angled airlock is letting co2 escape? I will just leave it for 7-10 days before taking a reading.

The recipe calls for a dry hop. I have ordered some muslin bags, is the process to stick some marbles in the bag after sanitising for about 5 days before bottling?

Having a fridge gives me the ability to do a cold crash. Having never done this before, I have read about suck back from the airlock. Would it be best to swap the lid to the bottling lid which has no airlock hole in, then cold crash to as low as the fridge can go for a couple of days? Should I do this after the 5 days of dry hopping, so 7 days in total before bottling?

Thanks

 

[Galena]

If you blank off your airlock hole, this is what I do for short cold crashes such as you describe. However I have very strong FV's which don't collapse under the vacuum created. So I guess it depends on what you're FV is made from and how well it seals.
For planned longer cold crashes such as lagering then I use a blowoff tube rather than a airlock and I made an expansion chamber out of a 5 litre water bottle, put it on while still fermenting and it fills with CO2, and then when cold crashed it sucks the liquid up into the expansion chamber but never reaches the FV. For dry hopping I have only ever used the former method.
There are some that use balloons filled with CO2 and others that probably just let air get sucked in. I have no idea how quick any oxygenation would spoil the beer, but perhaps if it is a beer to be drunk the ill effect would be minimal.