Fermented flavor Kaleidoscope (Under)1

The constant failure of fermentation in Homebrew can always produce ever-changing peculiar smell. Beer lovers usually spit out their tongues and make indescribable screams when drinking these homebrew works. For the sommeliers or beer referees who study wine tasting, these samples with 'the taste of the big fellow' will often become the 'tight goods' they are rushing to taste, and very seriously exchange experiences with each other. Of course, more serious people will spend thousands of yuan to buy some flavor reagents (Off-Flavor kit) In some non-public occasions, the colorful small bottles and capsules gathered together to pour these potions full of strange tastes into good wine, smelling, drinking and tasting. If you think they are crazy, then they are crazy and love what they love crazily. In other words, it is called 'persistence '! Flavor reagents so today we continue to talk about some headache organic chemistry topics! Of course, if you want to make good wine, these are also essential. Incredible phenolic substances let's introduce the phenolic substances produced by fermentation. Like esters, phenolic substances have good and bad, and there are many kinds. As for the fermentation results, it will depend on the fermentation conditions you provide. 1. 'Brett' style (4-Ethyl phenol) : It may be a bit awkward to say 'Brett', and the fans of 'Brett' should know something. 'Brett' is short for 'Brettanomyces' and translates as 'bouquet yeast '. It's a bit funny, the wine yeast can produce a very wide range of smells, its characteristics come from volatile phenols, can produce barns, stables, leather, wet haystacks, cherry pie, smoke, band-aid and other flavors. Wine yeast can bring clove, bacon, stables, band-aid and other flavor volatile phenol 4- Ethyl phenol is a characteristic substance for judging wine yeast, which can bring the smell of barn and Band-Aid. Many friends showed strange expressions when they smelled this smell for the first time, and kept asking whether the wine was broken or the smell? A proper amount of volatile phenols can be combined with the main taste of the base wine to make the aroma more complicated. An overdose will ruin a wine. 2. 'Clove' aroma (4-Vinyl guaiacol): 'Clove' flavor actually comes from 4- Vinyl guaiacol, a clove flavor, can be found in some wheat beer and Belgian beer. In the brewing process, you can increase this flavor by increasing the rest time of 45 °C and increasing the fermentation temperature in the saccharification stage. As a spice and a medicinal clove, it is different from the ornamental clove 3. Phenolic substances that should not appear in beer: chlorophenol will be generated if the water used in brewing is untreated, chlorine remains and reacts with phenol in wort, the beer has an astringent taste and a taste of cherry cough syrup, and the aftertaste is not scattered for a long time. This is usually the most easily discernible odor. If you often drink home-brewed beer, I believe you have also learned it. The 'vanilla' aroma in aldehydes beer actually comes from vanillin (4-Hydroxy-3-Methoxybenzaldehyde). Although vanilla also has the opportunity to produce such substances in the fermentation of beer, the best way is to use vanilla to enhance flavor or contact with oak, medium-baked oak can bring vanilla-like flavor to beer. In addition to phenol and Ester, other bad flavor of fermentation has obvious defects in flavor produced by fermentation. The following are some cases of 'shot' fermentation, which are caused by poor fermentation environment or improper fermentation operation. 1. Diacetyl: brings creamy popcorn flavor to beer. It is produced by yeast in the 'lag period' of the breeding stage. Under normal circumstances, diacetyl will be cleaned up by yeast after fermentation for two weeks. However, if the delay period is too long due to low temperature and insufficient yeast dosage, a lot of diacetyl will be produced so that yeast cannot completely clean them up at the later stage of fermentation, it will eventually lead to diacetyl in beer. 2. Acetaldehyde: acetaldehyde with green apple flavor is produced in the fermentation process, and the amount of acetaldehyde produced by different strains is different. Acetaldehyde is a very obvious odor and can usually be eliminated by prolonging the fermentation time. 3. Higher alcohol: it contains more than two carbon atoms (Ethanol contains 2 carbon atoms). Higher Alcohols appear when the fermentation temperature is too high or yeast nutrients are insufficient. ( Outside the question: in the production of Mead, insufficient yeast nutrition supplement will produce excessive higher alcohols. ) Thankfully, the vast majority of these good and bad flavors are under the control of winemakers. Even home-brewed products can obtain ideal flavors by regulating fermentation conditions. The purpose of speaking so many chemical words is not to cause dyslexia, but to make everyone pay attention to fermentation. After all, beer is made from yeast, respecting yeast, improving the working environment of yeast, clarifying the style of beer you want to brew, and making rational use of these preferences of yeast to make them work happily, brewing the taste you need is the original intention of this article. If you want to take it, you must give it first! I'm a little too much. Goodbye! Ferment well!