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Whole Cone Hops vs. Pellets vs. Extract

First off let’s look at a table where one can see the different yields from the brewhouse into finished beer of different hop products. These yields are based on the resulting amount of bittering compounds (iso-alpha acids) in beer in relationship to the amount of dosed alpha-acids of the hops when brewing beer.

One thing is certain; there isn’t any other topic that is so controversially discussed as hop products. Which ones should/could/are used? What are the differences between the hop products? Why is CO2 extract perceived as inferior? Is there something about these biases? Are whole cone hops really a “purer” product compared to pellets? Exactly this is what will be discussed in this article. Let’s start from the very beginning.

Whole Cone Hops

Whole cone hops are defined as harvested, dried and packed hops in 60 kg (~132 lbs) rectangular bales that are not processed or packaged with an inert gas. These bales should be used in the brewing process as soon as possible
What are the advantages and disadvantages of whole cone hops?

Querschnitt Hopfendolde
Grünhopfendolde

When you look at a hop cone from the outside, one will notice that it has a beautiful shape with different patterns of green tones. What one doesn’t see from the outside are the lupulin glands with the valuable contents inside. They are well-hidden on the strig, under the bracts and bracteoles. And exactly that is what makes it difficult for the wort/beer to get to the lupulin with whole cone hops. It needs to break the shell around the glands where the valuable contents are located. This is why the yield of aroma and bittering compounds is lower for whole cone hops in comparison to pellets.

The whole contents of the cone hops are not dissolved during the beer brewing process and need to be removed. Since the volume of the cone hops increased because of the liquid absorption, this can cause, to a certain extent, difficulties.
The advantage of whole cone hops is that they are not processed (except for dried and pressed in bales) and therefore also able to be used directly after the harvest. Also, leaf hops are somewhat cheaper than a processed product when purchased with the implication that they have a lower yield.
They also have a lower specific weight and increase the amount of storage needed. Whole cone hops are also not pressed into bales under inert gas and are therefore subject to oxidation. This causes a quicker aging of the hops.
All of these characteristics of whole cone hops makes the handling much more intense, which correlates more with the idea of “craft” and the old tradition of brewing.

Pellets

Pellets are, simply said, milled and pressed hops; nothing more and nothing less. Of 100 kg (~220 lbs) leaf hops, 93-96 kg (~205-211 lbs) pellets are produced during the normal pelletizing process. Everything else stays the same. The reduction in weight is caused by the cleaning and additional drying of the leaf hops.

The leaf hops are removed from the bales and are first mixed in a silo. After the initial mixture, they are milled, homogenized (mixed again), pressed into pellets, cooled and then packed with inert atmosphere.
After milling, the hops will have a larger surface area when dosed into beer. The lupulin glands will be partially broke open because of the milling process during the pelletizing process, which will lead to a better dispersion in beer and therefore a better yield.
During the processing of whole cone hops to pellets, an additional process step of sifting can also be completed to produce a pellet with oil and bitter compounds in a higher concentration, also known as enriched pellets. Since the aroma and bitter components are only found in the lupulin glands and these have a diameter of 0.15 mm (0.06 inches), the lupulin glands can be separated (sieved) from the rest of the material. The hops are milled at ca. -35°C and because the glands are frozen, they can be easily separated. Two fractions are then created: the fine fraction (= lupulin-enriched powder) and a coarse fraction (everything else). These two fractions can, within the processed batch, at will be mixed and therefore produce pellets with different alpha and oil contents. By the “removal” of spent hop material (the non-lupulin grand fraction), the product weight of the pellets will be reduced (high concentration of lupulin glands within the pellet). With less spent hop material, there will be fewer dosed particles in the brewing process for equivalent lupulin glands compared to the pellet process without sieving. There will then be less product to be removed later from the wort/beer.
Because pellets are packed in inert gas, they have a considerably longer shelf life and the aroma of the pellet stays stable longer. Their increased specific weight means less storage space for the same amount of product. Additionally, because pellets are homogenized during the pellet production, variances between the bitter and oil compounds can be compensated.

Extract

What is hop extract? Extraction is defined as a dissolution of a solid substance into a solution. The solvent (in the case for Barth-Haas supercritical CO2) that is used serves only as a means of transportation. By using supercritical CO2, the hop resin and oil (no polyphenols) are extracted out of the hop matrix. Once the process is completed, there is a pressure release (normal values are 300 bar or ~4350 psi!) and the CO2 will evaporate and the hop extract will separate from the CO2. As one can see, the process is completely physical, whereby the hop compounds are concentrated in a gentle way (while using a compound also created during the brewing process!)

Therefore, CO2 extract is the most pure product compared to leaf hops/pellets/extract, since the valuable hop substances (the bitter and oil compounds in the lupulin) exist in a more pure form. Problematic is when the extract wants to be added in the cold side of the brewing process since the resin and oil is difficult to dissolve at low temperatures. When used in the brewhouse (on the hot side), the yield is better. Since there are no solids in the extract, the access to the important compounds is much easier.

Comparison Pellets vs. Extract in Beer

An important question that we experience often is whether there is a difference in taste between beers using extract and with pellets.
If you look at the contents of hop products, it should become apparent: the more you process the hops, the more “pure” the valuable substances exist within that product. One should also notice that there are less polyphenols. And that brings us to the next question: how important are polyphenols for the taste of beer? Polyphenols are responsible for mouthfeel when they are dosed at the middle of the boil. Low molecular weight polyphenols have been shown to produce a pleasant bitterness, whereby the high molecular weight polyphenols have been shown to produce a harsh or astringent bitterness in beer.
What can’t be forgotten is the fact that protein and polyphenol compounds can cause poor haze stability.

How does this all affect the taste? Can one differentiate between beers that are produced with CO2 extract and beers with pellets?

We asked this exact question and brewed two beers that were identical except for the hop product. One beer was dosed with pellets and the other one with Herkules CO2 extract. Both beers had an original gravity of 13% and were fermented with a dry ale yeast from Fermentis. The dosage point was the same with both beers:

  • Dosage after boil in the whirlpool of 3 ml oil/hl
  • Dosage to the main fermentation of 3 ml oil/hl

In internal panels and also at the Braukunst Live! (craft beer festival in Munich), 92 people tried the beers in a triangle test. Here are the results:

Von den 92 Teilnehmern konnten 77 % die abweichende Probe erkennen.

Here are some comments why the beer with CO2 extract was preferred:

  • Stronger aroma
  • Less astringency
  • Pleasant bitterness
  • Better drinkability because the beer [with CO2 extract] had a lighter beer with a more pleasant aroma

 

Conclusion

Every product, whether it is whole cone hops, pellets or extract, can and will be used for brewing beer. Every one of these products has advantages and disadvantages and it is up to the brewery to decide which of these products are the best for them. What the same is for all of the products are the valuable contents: the hop oil and the bittering compounds. These exist unchanged in all three products, just the way these components are accessed during the brewing process is different.

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2 Responses to “Whole Cone Hops vs. Pellets vs. Extract”

  1. ozan yumrukaya says:

    Thank you very much about this detailed article. i would like to ask, in whirpooling, what should i think about utilization%. some says 10% but when i check tinseth chart, 5 minutes or less minutes, utilization % less than %10. i know that utilization still goes on because temperature is about 80 degree celcius. i m confused about ibu calculation in whirlpool.

    thank you very much

  2. Elisabeth Wiesen says:

    Dear Ozan,

    I am sorry, that I am not able to give you an exact answer but the best way to “calculate” your IBU would be to measure them. All calculations are an estimation and also based on experience, as each brewhouse is different and in each brewhouse you can have a different isomerization rate. The utilization is mostly closer to 5% than 10 %.

    I hope, this helps a little.

    Best regards,

    Elisabeth

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