Whole hop problem
I am on a quest to maximize the volume of beer I produce with each session, ultimately filling each corny keg to max capacity. As such, I am in the process of defining and marking volume levels in my various brewery vessels (kegs, carboys and boil kettle). I use a recycled commercial keg for the boil, modified with cutoff top, spigot and dip tube. When it came to determining the volume of dead space in the kettle below the dip tube, I ran into a conundrum using whole hops. How do soaking hops factor into this? Do they displace any appreciable volume of wort? My instinct from observing the floating hops is that the effect should be negligible (which would not be true if the hops submerged completely). Do pelletized hops behave any differently?
Todd Morgan • Olympia, Washington
I like the idea of marking all of your vessels so that you know the volume of what you are brewing at various steps. When you consider the fixed time required to brew a batch of beer it certainly makes sense to want to maximize your yield per batch. It also makes it much easier to hit your targeted original gravity and also to track yield if you’re into crunching numbers.
Wort losses after boiling are important to brewers of all sizes and wort loss in trub can be significant, especially in very hoppy beer. In my experience, wort losses are minimized by having a good method of separating hops from wort. To directly answer your question, hops do not displace much liquid and your vessel calibration should not have much error when you begin adding hops because there are simply not much hops added to wort, even in very hoppy beers.
Where things can become difficult, however, is when it is time to separate the wort from the hops. Carrying hops forward into fermentation is typically something that is intentionally minimized. Brewers using pelletized hops usually do this by using some sort of whirlpool method. Giving the wort a good stir after the boil has stopped works reasonably well in the type of kettle you have. The idea is to get the hops to form a mass at the bottom of the kettle where they hopefully remain while the wort is removed. In high gravity beers this doesn’t work so well because the hops are more buoyant due to the higher wort gravity. Couple this with the use of certain special malts and a high hopping rate and wort losses increase compared to a “normal” brew.
Reducing wort loss is one benefit of using cone hops. Since cone hops are removed with a strainer of sorts, wort loss is typically proportional to hopping rate because dry hops will absorb a given amount of wort per ounce. A hop strainer also acts as a filter for trub, and if wort gently flows through the hops retained in the strainer much of the hot break formed during boiling will be contained in the hop bed. If you are interested in doing something like this you could easily add a screen in your kettle and your wort losses will be minimized. Some brewers may be tempted to squeeze the spent hop bed to remove as much wort as possible, but this practice is not advised as it can extract stuff, like trub, that is best left behind.