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The long road to Descriptive Profiling, pt III

This is the last of three articles outlining the process of taking a taste panel from n00bs to rockstars.    The first articles covered setting up the tasting environment, training for flavor attribute recognition, attribute intensity training, and building a ballot lexicon.   This article will cover the actual flavor profiling, and how to manage the data and results.

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ASBC/MBAA meeting was very nice!

The “Brewing Summit” (the joint annual meetings of the ASBC and MBAA) in Chicago just concluded last Saturday and it was a lovely time.   It was the second time I’ve been to Chicago, and this time I was able to bring my spouse along with me and between the seminars, the sightseeing, and the friends/colleagues we saw, we had great fun.  I even got to wear a “Presenter” ribbon on my name tag – a first for me at an annual meeting for these organizations.   Hopefully I’ll get that opportunity again.   Although I didn’t cover the material quite as well as I’d like, I got some great feedback and plenty of compliments, so that was very nice.  That’s normal, though:  I often try to set my standards just out of my reach so I usually wind up a bit disappointed in the result.   It’s hard to feel confident in your material when you’re sharing the stage with some of the Titans of Sensory Science.

I also picked up a brand-new copy of Charlie Bamforth’s new book “Flavor” and got it signed by the Pope of Foam himself.   It’s not a big book, but it’s a great overview of many beer flavor issues, and it’s written in Bamforth’s conversational style so it’s quite entertaining as well.    Another high point was the “Pearls of Wisdom” talk where Oregon State’s Dr. Tom Shellhammer and Firestone Walker’s Matt Brynildson “debated” various hop topics, such as pellets vs. whole cone, Noble vs. American hops, kettle vs. dry-hopping, etc, only to be put in their place with facts from MillerCoors’ master hop chemist Pat Ting.  Very entertaining.  Wish you were there.

Best food I had while I was there?   Breakfast at West Egg Cafe on Fairbanks.   Their omelettes and potatoes were large and delicious, and service was fast, prices were good.

I took over 13 pages of notes for the events I attended, so once I get the electronic proceedings I’ll do some write-ups on the things I saw.   I promise!

Now I just need to dig out of this backlog of work and get this productivity train rolling again.

New Year, New Job, New Posts

Hello BSS Readers, and Happy New Year!

I hope the recent holidays have found you well. Again, I shall apologize for the lack of material that’s been showing up here. The last several months have been rather busy, I guess. I don’t really have a good excuse, but I do have some exciting news! I’ve got a new position in my company! In the next few weeks I am moving out of the quality control lab and taking a brand new position in the company (created just for me). This position will be part of a corporate-level service group designed to solve problems for the company. Part of my job will be to train *all* of our panelists across the company, which I’m actually already doing but this will be in an official capacity and will be more involved and will likely mean more traveling. Another part of my job will be poking through mountains of production data to look for issues and solve problems, and to create reports for the big wigs. I’m pretty excited about all the changes it will be bringing.

Once the dust settles after this transition (like the training of replacements, completion of remodeling projects, etc) I expect that I will have a little more time to put into this blog. I have some material from WBC that I still need to post, and I think I’ll have some other things to discuss as well by that time.

So, onward into 2013! This blog ain’t dead yet!

Analytical 2:

Analytical 2:

TALK 1: Recent discoveries in beer foam, Karl Siebert, Cornell

Best foam seen with lowest pH (3.?) and mid-range ethanol (5%), in an ovalbumin, isoalpha acid model system. Very simplified, so not totally accurate.

Above pH data was disputed in a study with actual beer (more foam at higher pH), so something was missing in the model system.

With an unmalted barley protein extraction, a higher pH and mid-range ethanol showed most foam, proving a better system than the ovalbumin model.

Seems like LTP1 protein is the main protein involved, and the interactions are mostly hydrogen bonding.

?s: should use malted barley as changed in proteins occur. Yes, I’m not done with this research yet. LTP1 has been shown to be responsible for gushing, does this disprove that? It may be a matter of degree, where normal beer hs the right conditions for moderate foam production.

TALK 2: Critical review of the measurement of carbon dioxide in packaged beer, Donald Hutchison, AB-InBev

Most instruments use pressure/temperature method. Must attemporate and equilibrate sample, correct for air altitude, and package volume.

TALK 3: CO2 solubility in wort and beers, R. Alex Speers, Dalhousie University

When is the beer saturated with CO2 (when bubble formation starts in fermentation)? pH, sugar, ethanol effects?

ASBC measurement is based on undefined reference standard beer, (sg 1.01, changed 1.015 for unknown reason. No chart or formula has provided justification. No presentation of data analysis of error. Formula says

ASBC method possibly used 95% of the value of CO2 solubility in water.

CO2 is 10x more soluble in ethanol than in water, so why does higher etoh content in beer have a negative influence on solubility as per the formulas?

(Findley, Shen, 1911, J. Chem Trans). The only report on CO2 solubility in beer?!

Why do we measure CO2 at higher temps? More accurate for reading gauges.

Need a tested and unified method, which includes factors for pH, ethanol, and extract, not just T and P.

?s: some reports on solubility ARE available, different formulas are available in the soft drink industry, although they also can’t establish origin. Now, ASBC methods have to be based on published papers. Have you investigated how large differences have to be until we can perceive differences in carbonation? Very small study showed no perceived visual differences from 2.2-2.7vol. (visual only?!?).

Barrel aging

Trilogy of Barrel aging

TALK 1: David Rosenthal, Chateau Ste. Michelle

Discussing barrel-making, oak growing regions and differences, differences in oak species

Sizes: 10-600L barrels… up to oak tanks, which are used for rieslings, as they do not much impart much oak flavor, but some mouthfeel.

Empty barrels are more vulnerable to contamination, ozone is best for cutting microbial growth. Sodium percarbonate, soda ash and citric acid are also used.

Wine tasting: 5 chardonnay samples, different producers and barrels.

1: Boutes, American Oak
2: Barrel Associates, American Oak, deep toast, (tastes like fireworks)
3: Boutes, French Oak, subtle and simple
4: Dargaud and Jaegle, French Oak
5: World Cooperage, French Oak (more fireworks)

He describes differences here, but I’m not super great at picking out barrel-based differences in wines.

TALK 2: Dr. James Osborne, Oregon State

Barrels are “good” for microbial growth due to rough surface, semi-porous so some access to oxygen, wood sugars can be used by some microorganisms (Brett).

Acetobacter: bad, almost always.
Lactobacillus: used to be used in ML fermentation (wine), now considered spoilage.
Pediococcus: can produce ropiness (extracellular polysaccharides) and lots of diacetyl.
Brettanomyces: “british brewing fungus”, a survivor, difficult to diagnose via microscopy, slow growing, poor competitor with Saccharomyces, don’t need oxygen but it can stimulate growth, can utilize many sugars even trehalose and ethanol, can penetrate up to 8mm into barrel staves.

Brett flavors: Lactones (b-damascenone), volatile phenols (4-et phenol, 4-et guaiacol), acids (acetic, isobutyric, isovaleric), alcohols, esters, lipid oxidation products.

Barrel maintenance: cannot fully eliminate all microbes, but topping off, use inert gasses, keep bung area clean, isolate infected barrels, santize thief, store empty barrels with compounds mentioned in TALK 1 (ozone is most popular).

TALK 3: Femke Sterckx, Wood Aging and Monophenols

25 different monophenols in wood-aged beer, many with vanilla or spicy characteristics. Precursors are lignin, hydroxycinnamic acids, some are bound in glycosides. Oak aging is often with oak chips. More wood chips are associated with higher monophenol content. Various compounds are more related with medium toasted barrels while others are more associated with heavy toasted barrels. Higher ethanol, higher lagering temperatures, and low pH helps with monophenol extraction.

Please excuse typos and shorthand. I tried, I really did. But the trip to Shangai Tunnel and elsewhere has left me sapped of the energy to proofread this material. Enjoy if you must.

Hops 1

Hops 1:

TALK 1: Influence of fermentation compounds from yeast on the quality of hop aroma, hitoshi takemura et al. , kirin

How can two breweries with same hop conditions result in beers of different hop aroma intensities?
Hypothesis 1: Biotransformation of hop oils by yeast?
Hypothesis 2: Do other yeast based compounds (esters) affect the perception of hops?

Testing 1: Results from GCMS does not support, as linalool levels are the same in “lower” beer (linalool is a typical indicator compound of hop aroma).

Testing 2: added esters and higher alcohols to beer (at ppm, and ppb levels, respectively) and tested by expert panel. Esters seemed to have no effect on hop fruity flavor, while higher alcohols (especially 1-pentanol, 1-heptanol) showed a suppression effect on hop fruity flavor. This supports hypothesis 2. Next, fermentation temperature (17, 21oC) and yeast pitching levels were tested. Again, put in front of small trained panel: temperature had a larger effect (higher temp leads to lower hop fruity flavor), and pitching rate had a less robust effect (higher pitching rate showed lower hop fruity character). Questions from audience: does aeration affect? Didnt test. Did you propagate yeast from same source? Yes. Were the spiked samples representative of normal beers for higher alcohol content? Yes (eg. 10-20ppb heptanol).

TALK 2: Aroma and Harvest maturity of hops, Daniel Sharp, OSU grad student

How does harvest time affect aroma chemistry, with Cascade and Willamette hops in particular? (hop oil in hops, not beer).

Hops from two farms, 2 years (2010, 2011), 3 harvest dates (early, trad., late). In triplicate. Extraction via ASBC steam distillation method, detected by HPLC and GC-FID. Harvest timeline: difficult to time the harvesting as “traditional” harvest time is usually a guessing game. Yearly climate differences also uncontrollable. Sample-sample variation between hop collection was large (three collections from whole hop field for each farm/variety).

Hop Storage Index: Very little difference due to harvest time.
Alpha acids: drop in the cascades at late harvest.

Cascade: (i cant keep up, moving too fast!).
Willamette: most terpenes increased over whole study, even into late harvest.
Sensory: only on cascade, difference test. Difference noted, so consumer acceptance test was performed. Trad harvest were preferred. Descriptive: late had more onion and garlic

Essential oil increases past harvest date for willamette, cascade stays constant or drops a bit.

?s: Bob Foster: Did you control kilning temps? Yes, 120F. Practical considerations for farmers? Need to nail down good useful predictor. Pellets vs whole? Used Whole. Did you look at dry matter content with harvest dates? No patterns, all over the place. Glycosides? No, Shellhammer will speak to that.

TALK 3: Patricia Aron, MillerCoors (and OSU)

Phenolic profiling of lager beers during aging in relation to hopping technology.

Some background on hop polyphenols, beer stability.

Hypothesis: hopping regime affects the phenolic profile over aging …(ack, too fast!). Focussing of flavonoids.

Method: 12p base wort, lager, Chelan hops. Accelerated aging (6 weeks). Hop treatments: control- no iso’s and no hop polyphenols; pellet- iso’s and hop polyphenols; spent- no iso’s with hop polyphenols; extract-alpha acids only.

Many analysis methods, broad and specific. Chock-a-block with chemistry, but it’s too fast too keep up with here. Increase in total polyphenols in aging, then a drop off as it ages further. More specific analysis of flavanoids/proanthocyanidins: spent hop beers were the highest (expected, due to the nature of the spent hop product). Spent hop beer saw the lowest increase of aldehydes over aging of the treatment beers. Methional (potato!) was the dominant aldehyde found in aging. no significantly different in trans-2-nonenal. Kettle hopping (pellets) did not augment proanthocyanidin content in beers. Hopping regime did not affect loss of iso-alpha acid content over aging. Brewing with hop products did not affect the antioxidant potential of beers by ESR (odd).

?s: what is the standard or definition for “spent hops”? There isn’t. Are you confident in your analysis of proanthocyanidins? Difficult, some material is not susceptible to acid cleavage. Does freezing/thawing have an effect? Dunno, but maybe.

TALK 4: Contributions to hop aroma from the water-soluble fraction of hops. Tom Shellhammer, Oregon State

Used spent hop material (after supercritical CO2 extraction) in lager beer, analyzed with sensory and instrumental. Simcoe, Centennial, Citra, Cascade. Very low level of residual alpha acids (highest was 0.5%, ~98% of the alphas were removed in extraction). Also very very low in residual hop oils. 1g/L hop addition, 5min into 60min boil.

3 finished beers: One with pellets (normal), one with hop extract (like Miller), one with spent hop material (water soluble materials). BU range: 18-37 (pellets), 12-15 (spent). Alcohol, 4% by weight. Spent hop beer showed surprising amount of linalool (order of magnitude). Principal Component Analysis showed spent and pellet beers in their own clusters, with the extract varieties separating out from each other.

Sensory: Spent hop beer aroma showed lower hop aroma intensity, as anticipated.

Summary: evidence that spent hop beers produce aromas that are noticeable and significant, and dependent on variety (particularly Simcoe).

?s: how was sensory performed on finished beers? Randomized, 5 reps minimum, difficult to control temperature due to randomization. Does the flavor result in a desire to brew with spent hop products? Didn’t look at preference or hedonics, but unofficial tastings showed surprising acceptance.

Please excuse any typos or shorthand, it’s late and my BAC is approx 0.2%, and I don’t have the energy to proofread.

Today’s plan for WBC: Hops 1, Barrel aging, and more?

Well, due to the lack of free wi-fi at the Hilton yesterday, I blogged the whole thing on my phone. Not fun. Today we’re at the convention center and I’m expecting there to be wi-fi so that I can use the iPad, which will actually be rather excellent in comparison.

Today I plan to attend the Hops 1 technical session, and Barrel aging. I don’t see much else on the schedule today that would catch my attention more than these (even skipping the keynote this morning, as Columbia Sportswear’s Tim Boyle doesn’t really lift my sails).

I’ll do my best to post stuff again today, so stay tuned.

Update: You’re telling me that wi-fi at the Oregon Convention Center costs $13 a day for 128K download speed? Have I found a wormhole to 1994?

This is ridiculous. No way am I going to do this on my phone again. I’ll have to take notes and paste them up later. Sorry.