How much weight to add to a dry-hop bag?

Question

It sounds like the best place for the bag of hops should be somewhere in the middle on the carboy (or other container). This will mean that no hops are sitting only half in beer which should increase the saturation of the hops while not dragging the bag all the way down to the bottom so it's sitting in the trub. ref: Is it important to weigh down a hop bag for dry-hopping?

I've heard many examples of objects to use as a weight, but is there a calculation for how much weight you would need to just counter the buoyancy of the hops? Or another method to accomplish the same task?

Answer 1

I don't use hop bags anymore (unless in the keg!) but when I did, I usually tied a piece of dental floss to the bag. I would whipe the floss with 70% Isopropyl Alcohol first, I'm sure your sanitizing agent will do the trick. Use glass beads as weights, sink the bag to where you want it, leaving the floss hanging out the top and insert the bung/ stopper! The nice thing about the floss is, if you want to remove the hops, you could. Again, my recommendation would be to just toss the hops into the carboy, no bag.

Answer 2

You can't get an object to float in the middle of the carboy without some kind of active boyancy management. A passive object will either float, from almost all above the beer surface, to until the entire object is just below the surface. Increasing the weight further will cause the object to sink, and continue to sink until it hits the bottom.

The exception is if you could obtain stratification in the wort, with higher density wort at the bottom. Then it would be possible to have the hops float in the middle if they were matched to the same density as the lower stratification layer. They would sink through the upper layer, which is lower density, but be supported by the lower, higher density layer.

This is all speculation, and IMHO, don't think the actual improvement in flavor extraction, if any, would be worth the effort. It may be simpler to use some thin stainless steel fishing twine tied to the weighted bag so it sinks and is held at the desired depth by the twine. The twine is thin enough to pass through the side of the stopper, or could be fed through the airlock.

EDIT: To directly answer the question about how much weight to add, you need to add the difference between the total weight of the bag and the hops, and the weight of the wort that occupies the same volume. In practice, this will be difficult to get right on every try. An alternative is to add more than enough weight to weigh down the hop bag, and then find a way of increasing boyancy, such as a small inflatable balloon on the end of a long thin hose (e.g. 4mm silicone aquarium hose.) Once the hop bag is submersed and the hops fully rehydrated, you can then get them to float by inflating the balloon with air. Include a suitable valve and the air will be maintained.

Although again, lots of effort for small gain, when a simple string or wire will do the trick to suspend the hop bag in the wort.

Answer 3

After trial and error, I add about a handful of those glass beads you put at the bottom of a flower vase. They're easy to boil sterilise along with what ever I'm putting the hops in. Works well for me.

Answer 4

Post answer selection answer here, but...

With a keg, tie floss to the bag per previous answers, push the bag in with 1/2 the keg height's worth of floss, and seal it up. Then turn the keg upside down for a while - the bag will float up right in the middle. After a while it will be sufficiently beer-logged to just sink on it's own, and you can flip the keg.

Answer 5

To achieve your desired mid-vessel placement, you could have a weight bag and a hop bag tied together with a short amount of monofilament. Since dry-hopping is typical in the later stages of secondary, the beer is already in contact with whatever trub is left so this might be overkill for most scenarios. (Should the hop bag sink once saturated it likely will not matter one bit.)

But if you are experimenting with earlier hopping while active fermentation is still proceeding, there is no reason you can't play with weights and floats as long as the objects are impermeable for easy sanitation and not going to leach lead or other nasty compounds into your beer.