Storing Down in Sealed Containers

[lilgumnut]

Everywhere I look I see recommendations to store down products in a breathable drawstring bag when not in use. However, with the recent mould explosion throughout Brisbane due to the high humidity and prolonged rains, I'm thinking that a sealed barrel with some silica packets might be a better way of protecting my down.

Does anyone know if there is a particular benefit to breathable storage that can't be achieved by sealed storage with silica?

[Gadgetgeek]

Probably just that most silica packs can't really absorb all that much moisture, and mainly just act as a moisture moderator. If you had some of the larger toolbox-sized packs that have the color change, that would give you a better indication of their effectiveness.
My understanding is that it's not just overall humidity that is the problem, but also temp changes causing moisture to migrate and condense, so breathable bags allow more airflow. I think that oxygen plays a role, and low oxygen can allow greater mold growth, but I may have that very wrong.

[lilgumnut]

Ooh these are some great points, thank you so much! With all of this considered it really seems like the breathable bags are the best option, perhaps with silica packets as an additional precaution.

For the sake of discussion:

The heat difference wouldn't be a problem if the atmosphere is completely dehydrated, but that would mean you'd have to dehydrate the dehumidification packets each time before you seal it, which is just another task.

I suppose the way to make such a situation work, then, would be to use a salt-based dehumidifier (the type that fill up with water over time) with silica perhaps mixed in to prevent the water from re-circulating (the salt dessicant removes the water from the atmosphere, the silica holds on to it).

Low oxygen definitely leads to nastier and smellier mould growth, that's for sure. But without moisture no mould is going to grow regardless of oxygen.

[Warin]

Some water absorbing silica changes colour with water absorption. Blue when dry and brown when wet, they can be dried out (an oven at 70 C should do) and reused. The problem with a sealed container is known it is dry in there, the colour changing silica is a very usefull feature.. I've used it for decades at work for valuable stuff in glass containers so you can see the silica colour. I'd not trust wet salt left in a container not to leave enough water behind for mold to grow.

[gbagua]

Not a good idea. Down needs to constantly breathe, otherwise the microscopic mould spores which are already living on the down item will proliferate out of control IF If moisture gets into a container before it’s sealed so there’s a good chance that mildew will grow and fester on your belongings and on the box itself. In that case down would become damp, soiled and in some cases, unsalvageable.

I'd personally, to avoid that risk, keep storing it in the breathable storage bag that was sold with the down product BUT from time to time (I do it weekly) gently blow the garment with a hair dryer inside and and also on the surface of the bag/jacket/etc.