What are Acetaldehyde, Conditioning, and Mouthfeel: Brewing Terminology Tuesday
February 17, 2015
Acetaldehyde Acetaldehyde is a compound that produces green apple flavor and aroma in homebrew, and is a byproduct of fermentation. However, one must remember that you need acetaldehyde in order to have beer! Why is this? Because acetaldehyde is formed during the conversion of sugar to ethanol by yeast. In simple terms: yeast creates acetaldehyde which is a precursor for alcohol… no acetaldehyde, no beer.The most common cause for acetaldehyde is removing your beer from the yeast to early, and not allowing the yeast to completely convert the sugar. If you can smell green apple and/or an acidic acid vinegar smell, you need to keep fermenting. Ways to avoid acetaldehyde being left in your beer after fermentation is too pitch more yeast and to make sure you have good temperature control. If, after fermentation you still taste or smell the green apple, you can still get rid of it with a good, long conditioning. On the flip side, ethanol (created by acetaldehyde) can create additional acetaldehyde through an oxidation process. Therefore, the best thing to do is to avoid oxygen contact post fermentation at all costs! Conditioning Conditioning refers to the time letting you beer mature and "condition." Over time, the flavor profile in your beer will mature depending on the type of conditioning. If conditioned in warm temperatures (room temp.) it will develop the complex flavors in your beer. If cold conditioned, it will develop a cleaner, rounder taste. Conditioning can be done in the bottles after carbonating, or in a conditioning tank where the beer is placed after primary fermentation to mature. When conditioned in a conditioning tank, it will naturally carbonate through second fermentation. Mouthfeel Mouthfeel is a term used when describing beer. When discussing mouthfeel, you are referring to the sensations you feel in your mouth and throat when you drink a beer, not what you taste. Different aspects that can attribute to mouthfeel are the weight on the tongue, carbonation, warmth, and astringency. The overall mouthfeel of a beer ranges from thin to full bodied. For a complete list of terms used when describing moutfeel, check out the wheel below.