T-45 versus T-90 Hop Pellets….
If you've ever wondered what these "T" values mean here is a great explanation from BYO.com's Ashton Lewis:
The “T” in T90 and T45 pellets is an abbreviation for “Type,” and the general designation relates the weight of the pellet to the whole hops coming into the process. One pound of whole cone hops yields about 0.9 pound (0.4 kg) of pellets in the case of T90 pellets, and 0.45 pound (0.2 kg) of pellets in the case of T45 pellets. At first glance it seems that the process used to make T45 pellets is only half as efficient as the T90 process, but when the alpha acid content is evaluated the difference has nothing to do with inefficiency; T45 pellets contain about double the alpha acids from the same cone hops as do T90 pellets.
This all makes more sense if the process of converting hop cones to pellets is briefly reviewed. Hops are harvested by cutting the entire bine (vine) free from the trellis and hauling this long plant into the hop processing shed. A series of specialized machines strip cones and leaves from the bine, and the cones are separated from the leaves. The cones are then loaded into the kiln, dried, and then (usually) compressed into hop bales for storage. It is imperative for hops to be harvested at just the right time and quickly processed into bales, because a delay at this stage can be detrimental to hop quality. The new bales are then transferred to cold storage where they await shipment to breweries using hop cones, or to processing plants that convert whole hops to pellets (there are a few farmers who skip the bailing process and go straight from the drying floor to the pelletizer, but this is far less common). Hop extracts are made from hop pellets (because the small, dense pellets are much easier to handle than cones).
The first step of the pellet process is converting bales into hop powder. The hop cone contains a central stem, or “strig,” that connects all of the “petals,” called bracts and bracteoles. The lupulin glands, those golden nuggets of hoppy goodness, are nestled at the base of the bracts and bracteoles. The strig is important to the hop cone because without the strig, there would be no cone or anything to hold the cone to the hop bine. But the strig has no brewing value, so it is removed before the hop cone is turned into a powder. This is where some weight is lost, and explains why T90 pellets are not T100 pellets. With T90 pellets, the bracts, bracteoles, and lupulin glands are milled into a powder, and then pressed into a pellet. The main advantages of the T90 pellet in comparison to whole hops are: Easier to handle, less costly to store and ship, improved storage properties, increased hop utilization, and easier to separate from wort. For these reasons, most breweries have migrated from whole cones to hop pellets over the last 30 years.
The T90 pellet is pretty simple and there are certainly some things about this product that can be improved. The most obvious is further removal of the parts of the pellet that have minimal brewing value. As stated above, the lupulin glands are nestled at the base of the bracts and bracteoles. If you take a hop cone and gently dissect it, you will observe that the tips of the bracts and bracteoles simply look like green petals, and you will observe that the lower portions are covered in a sticky yellow resin. The yellow, sticky stuff is really what brewers want from hops. Figure out a way to keep this stuff and minimize the non-essential parts and you have a concentrated hop pellet. In a nutshell, this is what happens when hop cones are processed into T45 pellets.
There are other things that can be done to pellets before shipping to the brewery. Pellets can be stabilized with calcium and/or magnesium, and can also be pre-isomerized. As the hop processor adds processing steps, the cost of the pellet increases, and the market for the pellet becomes smaller since not all brewers want the same sort of hop products. What this means for the homebrewer and smaller craft brewer is that access to T45 pellets, stabilized pellets, and pre-isomerized pellets is pretty limited. Any pellet hop you buy at a homebrewing store is likely a T90 pellet; if the pellet is a T45, or other further processed pellet, it will certainly be labelled as such and sold for a higher price.
The main reason that T45 pellets are used by commercial brewers is that they contain more of what is valued in hops, and less of what is not. In other words, there are economic reasons for commercial brewers to consider these pellets. Some breweries also are interested in sensory differences between T45 and T90 since the T45 pellet has less plant material. This difference is not a slam dunk benefit since hop flavor is complex, and the tannins from the “non-value” part of the cone does influence flavor. The real take-home message on this topic is that T45 pellets exist, sound really cool, but are not readily available to homebrewers. A few years ago I wanted to try using T45 pellets for aroma and started looking for sources, and was bummed out to learn that only a few varieties are readily available to commercial brewers, and these varieties are “bittering” varieties. I hope you were not getting too excited about T45 hops, but I hope understanding this the difference and process is still of value.
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