Dry Hopping - a new look at Techniques, Efficiency and Economics. Ray Marriott Totally Natural Solutions Ltd, UK 22 nd January 2019

Transcription

1 Dry Hopping - a new look at Techniques, Efficiency and Economics Ray Marriott Totally Natural Solutions Ltd, UK 22 nd January 2019

2 Dry hopping is a pain! Hops and pellets (to a lesser degree) are bulky and unstable and ideally need cold storage Only a small proportion of the brewing value is used in dry hopping Efficient dry-hopping requires capital investment and equipment can be occupied for days Beer losses are substantial at high hopping rates As highly hopped beers gain in popularity translation to large scale production introduces significant handling issues

3 Project Objectives Identify key parameters that impact the transfer of hop aroma molecules to beer Understand the mechanism of hop derived molecule distribution in the final beer Develop a model to predict hop aroma profile in the final beer Develop alternative strategies for more efficient and economic dry hopping

4 Project plan Review existing optimisation data Fix known optimum parameters Select variables Hop analysis Dry hopping trials Beer analysis Physicochemical data of metabolites Process modeling Product development

5 Dry Hopping Parameters

6 Dry hopping trial procedure 5% ABV un-hopped beer base used Dry hopping added as hop pellets T90 or extracts Temperature for all trials 5 o C Equilibration time 24 hours with stirring Beer clarified by centrifugation and filtration Hop aroma analysis by headspace SPME with GC- MS [1] Non volatile molecules not considered Li, H., Liu, F., Kun-Farkas, G., & Kiss, Z. (2015). Quantitative Analysis of Flavor Volatiles in Beer Using Headspace Solid-Phase Microextraction and Gas Chromatography Flame Ionization Detection (HS-SPME-GC-FID). J. Am. Soc. Brew. Chem, 73(3),

7 Cascade hops Single grower source(us, Oregon) Alpha acid content 8.0% Oil content 2.0% Composition: Myrcene 58% Humulene 16% Caryophyllene 7% Farnesene 6% Linalol 0.6% Geraniol 0.2%

8 Cascade hops TIC Myrcene Humulene Farnesene Caryophyllene Linalol Geraniol Methyl geranate Geranyl acetate

9 Cascade hops EIC m/z 69 Myrcene Caryophyllene Farnesene Geranyl acetate Humulene Geranyl iso-butyrate Linalol Geraniol Methyl geranate

10 Headspace SPME analysis 1.00g of degassed beer is weighed into a SPME vial and 200mg salt (NaCl) added. A small magnetic stirrer is placed into the vial which is then capped and equilibrated for 10 minutes at 40 o C with constant stirring. After equilibration, a 50/30μm Divinylbenzene/Carboxen/Polydimet hylsiloxane (DVB/CAR/PDMS) fibre is exposed in the headspace of the vial under the same conditions for 10 minutes. After absorption, the fibre is retracted and desorbed for 1 minute in the GC- MS injector (250 o C).

11 Cascade single hopped beer Headspace SPME GC/MS Ethanol 2. Ethyl acetate 3. 2-methyl-1-propanol 4. 3-methyl butanol 5. 2-methyl butanol 6. i-amyl acetate 7. Myrcene 8. Ethyl hexanoate 9. Linalol 10. Phenyl ethanol 11. Octanoic acid 12. Ethyl Octanoate 13. Citronellol 14. Geraniol 15. Phenyl ethyl acetate 16. Methyl geranate 17. Geranyl acetate

12 Pellet dose rate Mean data from triplicate trials

13 Impact of hopping rate on concentration µg/l g/hl

14 Impact of hopping rate on transfer rate % g/hl

15 Impact of hopping rate on concentration

16 Hop aroma profile vs dry hopping rate Overall hop intensity Herbal/Tea Citrus LaFontaine S., Proc. 36 th EBC, Slovenia 2017

17 Impact of hopping rate on % beer loss Beer loss (%) Pellet dose rate (g/hl)

18 Trial conclusions Increased hopping rates do not result in a linear increase in final flavour and aroma levels and can introduce undesirable flavours Beer losses resulting from higher hopping rates have a significant impact on brewing economics Alternative strategies such as the use of concentrated pellets or lupulin powders can partly mitigate these losses but brewers report handling problems A greater understanding of the mechanism of hop aroma transfer from hops to beer has been used to develop a hop extract approach Using a hop extract approach also preserves α-acid value

19 Properties of key hop molecules

20 Solubility of hop oil molecules in beer Headspace SPME GC/MS Ethanol 2. Ethyl acetate 3. 2-methyl-1-propanol 4. 3-methyl butanol 5. 2-methyl butanol 6. i-amyl acetate 7. Myrcene 8. Ethyl hexanoate 9. Linalol 10. Phenyl ethanol 11. Octanoic acid 12. Ethyl Octanoate 13. Citronellol 14. Geraniol 15. Phenyl ethyl acetate 16. Methyl geranate 17. Geranyl acetate 18. Caryophyllene 19. Humulene All hop molecules are soluble in water at a significantly greater level than found in dry hopped beer

21 Partition of key hop molecules Log K ow (n-octanol/water Partition Coefficient) or Log P is defined as the ratio of the concentration of a molecule in n- octanol and water at equilibrium at a specified temperature. Log K ow values are unit less and are a relative indicator of the tendency of an organic compound to adsorb to biomass Values >4.5 are known to absorb strongly The implication of the range of Log K ow values is that partition of these molecules is key to the distribution in beer

22 Correlation of Log K ow values

23 Hop extract solutions Image from Hop oil scco 2 Reverse phase chromatography Normal phase chromatography

24 Chromatographic fractionation Hydrocarbons - myrcene, humulene, caryophyllene Esters - methyl esters C 6 C 14 Epoxides Ketones Alcohols Fatty acids - humulene epoxide II - undecan-2-one - linalol, geraniol, humulenol II - isovaleric, geranic, trans-4-decenoic Increasing polarity Marriott, R.J., Patents EP , WO , 2015

25 Hop oil fractionation Pellets T90 CO 2 extraction Hop oil CO 2 fractionation Aroma fractions Hydrocarbons Esters Ketones epoxides Alcohols Aroma molecules myrcene humulene caryophyllene i-amyl-i-valerate methyl geranate geranyl esters 2-undecanone humulene epoxide caryophyllene oxide linalool geraniol 2-humulenol Processing using green solvents including SFC (Marriott, R.J., Patents EP , WO , 2015)

26 Dry hop profile creation Cascade Pellets E=95% E=95% CO 2 extraction Cascade hop oil CO 2 fractionation Oil reduced residue CO 2 extraction (E=93%) Hydrocarbons Esters Ketones epoxides Alcohols α-acids 40% 11% 2% 47% E=100% Cascade dry hop 500

27 Dry hop profile creation Cascade pellets 500g/hl Myrcene Cascade dry hop extract 500 Myrcene Linalol Geraniol Geranyl acetate Citronellol Methyl geranate

28 Commercial applications US Craft Brewer (100,000BBL/annum) Pilsner 4 hop varieties used, analysis and organoleptic evaluation resulted in hop aroma match Beer flavour and flavour stability improved, 10% reduction in hop costs and 18% reduction in beer losses. $150k/month savings IPA (70 BU, 6.5% ABV) Replacement of 5 hop varieties with single hop aroma extract, less cold storage required and reduced inventory Beer losses reduced by 27% and vessel occupancy by 12 days Cost reduction $285k per annum Other applications have used partial replacement to dry hops to reduce beer losses while maintaining flavour level

29 Conclusions Transfer of aroma molecules from hops to beer appears to be predicted by a partition model Transfer efficiency reduces as hopping dose increases and concurrently beer losses rise As dry hopped beers reach mainstream volume more efficient strategies are needed Using hop extracts reduces or eliminates beer losses and makes efficient use of hops as α-acids can be recovered This alternative to dry hopping can be used in all beer styles, low alcohol beers and NABs

30 Future work Expand model to include a greater range of parameters, particularly ABV, fermenter addition and filtration Correlate analytical model with organoleptic data Apply model to greater range of hop varieties and variety mixtures Carry out more commercial brewing trials to generate more robust data we welcome participation from all brewers

31 Some suggestions Excessive levels of dry hopping are counter productive and should probably be capped at g/hl Use the most efficient dry hopping equipment you can afford Consider using a proportion of post fermentation addition of both aroma and bitterness to increase efficiency and reduce costs Thee is no perfect solution and TNS will work with brewers for find the best solution for their products

32 Natural hop products

33 Beer Tasting Beers and a selection of zero alcohol beers prepared with hop products will be available for tasting this afternoon Session Session Max 20 delegates per session

34 Thank you for your attention!