Owen Ogletree owen.ogletree@brewingnews

1. Owen Ogletreeowen.ogletree@brewingnews.com • Introductions • Why craft brewing is an art form • Fermentation by-products / off-flavors • Three beers deconstructed • Beer Pairs: similarities & differences • Yeast notes

2. Introductions • Your name • How you fell in love with craft beer

3. Pair Up A = who got up earliest this morning B = who got up later

4. Agree or Disagree? • Czech Light Lager & Czech Imperial Lager are new BJCP styles. • The lowest average ABV style in the BJCP “Brown British Beer” group is “British Brown Ale.” • Skunk-like notes in beer are usually caused by old hops. • Diacetyl’s (butterscotch) precursor has no perceptible aroma or flavor. • Sherry notes can often be picked up in malty beers with considerable age.

5. A Tale of Three Beers Similar SRM (standard reference method) colors, ABV, and IBUs. How do they differ from each other? Possible causes of these differences?

6. Brewing Bingo

7. BJCP Update • Beer styles are constantly evolving.

8. Comparison: Beer Style Stats

9. Comparison: Beer Style Stats

10. Comparison: Beer Style Stats

11. A / B Discussion • “A” – Would you consider making a Berliner Weisse or Lambic in your brewery? Why or why not?

12. Comparison: Beer Style Stats

13. Comparison: Beer Style Stats

14. A / B Discussion • “B” – Talk to your “A” partner about how a Barleywine and Imperial Stout are similar and different.

15. Comparison: Beer Style Stats

16. Comparison: Beer Style Stats

17. Comparison: Beer Style Stats

18. Comparison: Beer Style Stats

19. Comparison: Beer Style Stats

20. A / B Discussion • “A” – What are your thoughts on the future of popular Hazy “New England” IPAs?

21. Comparison: Beer Style Stats

22. Comparison: Beer Style Stats

23. Let’s Judge a Beer! • Use the style guidelines sheet. • Note any “off” notes on the check boxes to the left • Add up your score • Doesn’t have to be perfect or detailed

24. Types of Brewing Yeasts • Two types of brewing yeasts, originally classified on flocculation behavior… • Top-fermenting – NAME CHARACTERISTICS • Ale yeast • Weiss yeast • Bottom-fermenting – NAME CHARACTERISTICS • Lager yeast Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

25. Ale Yeast • Predominant brewing yeast prior to the mid-1800s. • Displaced by lager yeast • Strains are genetically more diverse - several origins • Warm fermentation temperatures: 65 to 72 °F. Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

26. Weiss Yeast • Bavarian origins - closely related. • Produces beer that has spicy, clove, vanilla, and nutmeg flavor notes. • Warm fermentation temperatures: 65 to 72 °F. Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

27. Lager Yeast • Bavarian origin. • 1400s in Munich - cool fermentations (selective pressure) • Taken to Pilsen and Copenhagen in 1840s • Became very popular • Popularity fueled by advances of Industrial Revolution • Steam power, refrigeration, railroads, pasteurization and filtration technology • Strains are closely related - common origins • Cool fermentation temperatures: 42 to 52 °F • Beers are more delicate, clean, drinkable, and less aromatic. Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

28. Yeast Metabolism During Fermentation Sugars Oxygen Membranes Glucose CO2 Energy Unsaturated Fatty Acids Sterols Esters Pyruvate Ethanol Higher Alcohols TCA Cycle Amino Acids Acetaldehyde Diacetyl Organic Acids Sulfur Volatiles Amino Acids Kindly provided by Tom Pugh and David Ryder of Miller Brewing Company

29. Four Corners Choose a corner that represents the beer off-flavor that YOU see as the biggest off-flavor problem in craft beer today. Walk to the corner and discuss with others in that corner.

30. FermentationBy-Products & Off Flavors • Estersare fruity notes that may be controlled by the choice of yeast strain, wort gravity, and fermentation temperature. • In general, ale yeasts produce higher ester levels. Lager yeasts can, if fermented too warm, also produce esters (French Bière de Gardestyles). • Wort gravity also is a factor; the hallmark esters of Belgian Trappist styles are not only due to the yeast strains used but also a result of their high gravity wort. • A four-fold increase in ester production may be observed as a result of increasing the fermentation temperature from 60 to 68 °F. www.BJCP.org

31. FermentationBy-Products & Off Flavors • Fusel alcoholsare metabolized from amino acids. • Their production is increased as the fermentation temperature is increased. • Also, like esters, fusel alcohols increase with wort gravity. • Various wild yeasts tend to produce excessive amounts of fusel alcohols; hence proper sanitation is important for their reduction. • (B) www.BJCP.org

32. Fermentation By-Products • Diacetyl is responsible for an artificial butter or butterscotch aroma and taste. • A significant number of tasters cannot perceive diacetyl at any concentration. • Diacetyl is a fermentation by-product. • Diacetyl is also produced by lactic acid bacteria, notably Pediococcusdamnosus. Low levels of diacetyl are permissible in nearly all ales, particularly those brewed in the United Kingdom, and even some lagers, notably Czech pilseners. www.BJCP.org

33. Fermentation By-Products • Diacetyl is produced at the beginning stages of fermentation and then later reduced. • Maintaining or even increasing the temperature at the end of fermentation can help in its reduction, as will not prematurely removing the beer from the yeast. • Oxygen reintroduction can cause its formation through oxidation of diacetyl precursors present in the beer. • In the case of diacetyl, the flavorless precursor is alpha acetolactate (AAL). Once outside the cell, alpha acetolactate can be oxidized to diacetyl. • Diacetyl removal is helped by a strong, rapid fermentation performed by well-aerated, correctly pitched yeast. A large, early reduction in wort pH, and the prevention of further oxygen uptake later in the fermentation will also help. • A short period (two days) of warm conditioning around 68 degrees F will help to convert all of the precursor still in the wort into diacetyl. • It is essential that enough live, active yeast are present during maturation to remove the remaining diacetyl. www.BJCP.org

34. Simple Diacetyl Test Place a sample of your young beer in two glasses. Cover and put one in ahot water bath for 10-20 minutes, while keeping the other at room temperature. Cool the hot beer to about the same temperature as the cool sample; a cold water bath can be used to good effect for this. Remove the covers and smell each sample. One of the following conditions will exist:1. Neither beer smells buttery. This is good! It means that all of the alpha acetolactate (AAL) has already been converted to diacetyl and your beer is ready for packaging.2. The heated sample smells buttery, but the cold one does not. This means that there is excessive AAL still floating around your beer, and you should age it at 60 °F or so for a few days to allow diacetyl to form and then be metabolized by the yeast. Repeat the test to determine the proper time for packaging.3. Both samples smell like butter. This can be a bad thing. It can be indicative of a Pediococcusinfection, in which case you should dump the batch and start over, or it can mean that your yeast is incapable of metabolizing diacetyl (respiratory mutants). http://www.professorbeer.com/articles/diacetyl.html

35. Off Flavors • Acetaldehydehas the taste and aroma of fresh-cut green apples, and has also been compared to grass, green leaves and latex paint. • It is normally reduced to ethanol by yeast during the secondary fermentation, but oxidation of the finished beer may reverse this process. • Elevated levels are generally present in green beer or if the beer is prematurely removed from the yeast. • It can also be a product of bacterial spoilage. • Can contribute a pleasant “house” quality to some beers, like those from Samuel Smith in the UK. www.BJCP.org

36. Off Flavors • Astringencyis a mouth-puckering sensation comparable to chewing on grape skins or grape seeds. • It is often produced by the extraction of tannins from grain husks due to over-crushing, over-sparging, or sparging with water with a pH over 6.0 and a temperature higher than 170 °F. • Astringency may also be produced by polyphenols that result from spoilage by acetobacter or wild yeast. • Finally, spices such as coriander, orange peel and cinnamon also contribute astringent flavors. Some high-AA hops may also produce astringency. • Note that over-attenuation and low dextrin levels can increase the perception of astringency. • (D) www.BJCP.org

37. Off Flavors • DMS, or dimethyl-sulfide produces the aroma and taste of cooked vegetables -- notably corn, celery, cabbage or parsnips. In extreme cases, it may even be reminiscent of shellfish. • Most DMS precursors evaporate during a long, open, rolling boil. A short, weak or closed boil, or slow cooling of the wort may lead to high levels. • Some DMS is also scrubbed out during a vigorous fermentation. • Wild yeast or bacteria may produce high levels of DMS. • Pilsner malt contains as much as eight times the DMS precursor levels of pale malt, so Pils-based beers sometimes have a DMS character. Low levels of DMS are appropriate in some Pils-based lagers -- particularly American light lagers and Classic American Pilsners. • (S) www.BJCP.org

38. Off Flavors • Lightstruck/Skunky. This aroma and taste is due to the presence of the same mercaptans that are found in the scent glands of skunks. • Formed when UV light cleaves an isohumulone molecule, and the resulting radical combines with a sulfur compound. • Beer stored in clear or green glass bottles is more susceptible to this reaction, which is why brown glass offers more protection. Cans offer perfect protection. • Lightstruckflavors are not desirable in any style, but many European imports possess this quality. • (o) www.BJCP.org

39. Off Flavors • Paper/Cardboard/Oxidationnotes are perceived in both aroma and flavor. • The threat of oxidation may be reduced by minimizing splashing of the hot wort or of the fermented beer while racking or bottling. • This flavor is never appropriate, but it is a common flaw in many old or abused commercial beers. www.BJCP.org

40. A / B Discussion • “B” – Discuss with “A” your thoughts on how bottle-conditioning influences shelf life of a beer. (ac)

41. Lactic Acid The most common souring agent in beer is lactic acid, which gives a clean, sharp sourness. Lactic acid is produced by rod-shaped Lactobacillus. Lactobacillus bacteria is also used to create yogurt. Unfortunately, it is a common wild bacteria. Another source of lactic acid in beer is spherical Pediococcus bacteria that can also produce diacetyl.

42. Off Flavors • Sherry-likeis the aroma and taste of dry sherry and is often accompanied by hazelnut or almond notes. • The responsible compounds are oxidized members of the melanoidin family. • This flavor is one of the few positive flavors attributed to oxidation and adds complexity to barleywines and old ales. www.BJCP.org

43. Off Flavors • Sulfury/Yeastyflavors have the aroma and taste of rotten eggs, shrimp or rubber. • The compounds responsible for these flavors originate from certain sulfur-containing amino acids. • Possible sources include yeast autolysis, bacterial spoilage and water contamination. • (Ph) www.BJCP.org

44. Off Flavors • Phenolicis an aroma and taste often compared to Band-aids or disinfectant. • Chlorophenolsare particularly offensive members of this family with bleach-like flavors. • High levels of phenols are generally produced by bacteria or wild yeast, both of which indicate a sanitation problem. • Phenols may also be extracted from grain husks by over-crushing, over-spargingor sparging with hot or alkaline water. • Chlorinated water and sanitizer residue are possible sources of chlorophenols. • Phenolicflavors are generally never desirable, the exception being the pleasant, clove-like, vanilla-like or slightly smoky flavors and aromas in Bavarian wheat beers and some Belgian ales. www.BJCP.org

45. Questions or Comments?Owen Ogletreewww.Brewtopia.infoowen.ogletree@brewingnews.com