dry hopping - a new look at techniques, efficiency and … · 2019-01-25 · j. am. soc. brew....
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Dry Hopping - a new look at Techniques, Efficiency and
Economics
Ray MarriottTotally Natural Solutions Ltd, UK
22nd January 2019
Dry hopping is a pain!
© TNS 2019
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
Project Objectives
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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
Project plan
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Review existing optimisation data
Fix known optimum parameters
Select variables
Dry hopping trials
Beer analysis
Hop analysis
Physicochemical dataof metabolites Process modeling
Product development
Dry Hopping Parameters
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Dry hopping trial procedure
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5% ABV un-hopped beer base used
Dry hopping added as hop pellets T90 or extracts
Temperature for all trials 5oC
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 consideredLi, 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), 261-265.
● 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%
Cascade hops
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Cascade hops
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Caryophyllene
Humulene
Farnesene
Myrcene
TIC
LinalolGeranyl acetate
GeraniolMethyl
geranate
Cascade hops
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Caryophyllene
Humulene
FarneseneMyrcene
Linalol
Geranyl acetate
Geraniol
Methyl geranate
Geranyl iso-butyrate
EIC m/z 69
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 40oC with constant stirring.
After equilibration, a 50/30μm Divinylbenzene/Carboxen/Polydimethylsiloxane (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 (250oC).
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Cascade single hopped beer
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1. Ethanol2. Ethyl acetate3. 2-methyl-1-propanol4. 3-methyl butanol5. 2-methyl butanol6. i-amyl acetate7. Myrcene8. Ethyl hexanoate9. Linalol10. Phenyl ethanol11. Octanoic acid12. Ethyl Octanoate13. Citronellol14. Geraniol15. Phenyl ethyl acetate16. Methyl geranate17. Geranyl acetate
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Headspace SPME – GC/MS
Pellet dose rate
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Mean data from triplicate trials
Impact of hopping rate on concentration
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µg/l
%
g/hl© TNS 2019
Impact of hopping rate on transfer rate
Impact of hopping rate on concentration
Hop aroma profile vs dry hopping rate
LaFontaine S., Proc. 36th EBC, Slovenia 2017
Citrus
Herbal/Tea
Overall hop intensity
© TNS 2019Pellet dose rate (g/hl)
Beer loss (%)
Impact of hopping rate on % beer loss
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
Trial conclusions
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Properties of key hop molecules
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1. Ethanol2. Ethyl acetate3. 2-methyl-1-propanol4. 3-methyl butanol5. 2-methyl butanol6. i-amyl acetate7. Myrcene8. Ethyl hexanoate9. Linalol10. Phenyl ethanol11. Octanoic acid12. Ethyl Octanoate13. Citronellol14. Geraniol15. Phenyl ethyl acetate16. Methyl geranate17. Geranyl acetate18. Caryophyllene19. Humulene
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Headspace SPME – GC/MS
Solubility of hop oil molecules in beer
All hop molecules are soluble in water at a significantly greater level than found in dry hopped beer
Partition of key hop molecules
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Log Kow (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 Kow 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 Kow values is that partition of these molecules is key to the distribution in beer
Correlation of Log Kow values
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Image from https://braukon.de/en/hopgun/
Hop extract solutions
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Hop oil
scCO2
“Reverse phase chromatography” “Normal phase chromatography”
Increasing polarity
Hydrocarbons - myrcene, humulene, caryophyllene
Esters - methyl esters C6 – C14
Epoxides - humulene epoxide II
Ketones - undecan-2-one
Alcohols - linalol, geraniol, humulenol II
Fatty acids - isovaleric, geranic, trans-4-decenoic
Marriott, R.J., Patents EP2865746, WO2015062745, 2015
Chromatographic fractionation
Hop oil fractionation
Pellets T90
Aroma fractions Esters Ketones
epoxidesAlcoholsHydrocarbons
linalool
geraniol
2-humulenol
Aroma molecules
i-amyl-i-valerate
methyl geranate
geranyl esters
myrcene
humulene
caryophyllene
2-undecanone
humulene epoxide
caryophyllene oxide
Hop oil
Processing using “green” solvents including SFC (Marriott, R.J., Patents EP2865746, WO2015062745, 2015) © TNS 2019
CO2 extraction
CO2 fractionation
Dry hop profile creation
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Cascade Pellets
Esters Ketonesepoxides
AlcoholsHydrocarbons
Cascade hop oil
CO2 extraction
CO2 fractionation
Oil reduced residue
CO2 extraction (E=93%)
α-acids
40% 11% 2% 47%
Cascade dry hop 500
E=95%
E=95%
E=100%
Dry hop profile creation
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Myrcene
Linalol Geranyl acetateGeraniol
Methyl geranateCitronellol
Myrcene
Cascade pellets 500g/hl
Cascade dry hop extract 500
Commercial applications
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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
Conclusions
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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
Future work
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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
Some suggestions
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Excessive levels of dry hopping are counter productive and should probably be capped at 800-1000g/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
Natural hop products
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Beer Tasting
Beers and a selection of zero alcohol beers prepared with hop products will be available
for tasting this afternoon
Session 1 - 15.00 – 15.20
Session 2 – 15.30 – 15.50
Max 20 delegates per session
