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We dry-hop because it can make SUPER HOPPY beer that is not necessarily super bitter. Basically hops have two things: resins and oils- the resins when boiled in the brewhouse kettle (isomerized) create bitterness- it must be boiled b/c at that point we only have resin (oil) and wort (water) which do not mix, but when we boil, they become one (and in the process create bitterness).
The essential aroma oils (myrcrene, linalool, geraniol) are super heat sensitive and will volatize when heat is added so when hops are added in the brewhouse kettle, most of the delicate oils volatize into steam and are condensed and carried away- bummer. We can add them later in the boil to try and keep some but most are driven away. BUT, if we add more hops after fermentation has occurred at relatively cooler temps then we have ethanol which is a solvent that these oils can get with. That and because we are not boiling, there is only the addition of aroma and flavor (citrus, fruity, floral, piney, grassy, spicy) and no more bitterness. SO - as mentioned above - you can make a SUPER HOPPY beer that is not necessarily super bitter.
Dry-hoping uses more water because there is more movement of beer and more tank cleaning, both of which require water.
Here at NBB when we dry-hop a batch of beer, we use a sophisticated approach. We do this by employing both a system of moving the beer, and a special recirculation tank to achieve the dry-hop flavor and aromas in a very efficient manner. This does involve moving the beer around our cellar a little more than usual, and so requires more cleaning and water usage than for our non-dry-hopped beers. To move the beer from tank to tank in the cellar, we have a pair of system of pipes, pumps, heat exchangers, dosing vessels and centrifuges; this system is called “the Chiller”. The Chiller as well as the tanks involved must be cleaned between batches to achieve the sanitation required in making beer. This process, called CIP (clean in place) uses water along with chemicals to do the cleaning. The beer moving through our chillers, also uses water to keep the beer safe from oxygen, and to push the beer along at the end of the transfer. All of our beers, dry-hopped or not, go through this process of moving through “the chiller” as it’s how we remove much of the yeast via the Centrifuge, allows us to combine batches to fully utilize our tank space in the cellar by filling tanks to capacity, and cool the beer rapidly and efficiently with the integral heat exchanger, aka ‘The Chiller’.
When we dry-hop, we make 2 passes through the chiller system. On the first pass, we remove the yeast with the centrifuge and add the hops as we fill one of our recirculation tanks. When the beer has made it completely into the recirculation tank, we then start moving it right back out on The Chiller. This time the centrifuge is used to remove the hops from the beer as we fill another (3rd) tank and we use the heat exchanger to cool the beer down to maturation temperature of below 0 Celsius. So this double pass through the chiller requires twice as much push water as a non dry-hopped brand, as it takes 2 passes through the chiller. Also, it involves an additional tank, which requires cleaning and more water. All this contributes to why dry-hopped beers contribute more loading to our water-wise conservation efforts, compared to our non-dry-hopped brands.
Save The Colorado: The Save the Colorado campaign was initiated by New Belgium and the Clean Water Fund in 2009. Now a coalition of seven sustainably driven companies and foundations, we donate money, raise awareness and advocate for policy to promote water conservation and protect the threated Colorado River, which over 30 million people depend upon for food, water, and energy.