Yeast Smell in a fermenter

Yeast odor is an unpleasant odor, especially when yeast autolyses. Yeast-smelling beers are often characterized by high pH, dark color, and poor foam performance.

The main reasons for yeast odor during fermentation in conical tanks are as follows.

• The temperature control is unreasonable. At the end of the diacetyl reduction, the temperature difference between the lower section and the middle and upper sections is too large, which will cause strong convection in the wine, resulting in the difficulty of yeast precipitation and autolysis.

• If the amount of yeast added is too large, or the number of generations used is too large, the aging of yeast is prone to autolysis.

• High storage temperature and long storage time lead to autolysis of yeast and release of fatty acids. These substances impart an unpleasant aroma to the fermentation broth and negatively affect foam, with ethyl acetate and ethyl laurate together creating a yeasty flavor at higher levels.

• The precipitation yeast was not discharged in time, the old and weak yeast stayed in the tank for too long, and the accumulation of yeast at the bottom of the tank affected the cooling effect, resulting in the yeast at the bottom of the tank being in a high temperature state for a long time, resulting in the yeast autolysing and dispersing into the liquor , which brings yeast and post-bitterness to the fermentation broth.

• Hygiene issues like plumbing or mold dead end growth can also cause yeast odors in the fermentation broth.

Cleaning agents for beer brewing equipment

For beer brewery equipment cleaning, we all know that the cleaning agents is the mainly factor that influence the cleaning result. A good cleaning agent should be: easily dissolved in water; easy for cleaning; no corrosion for raw material; do not react with the salt in water; low cost; convenient for usage and lower pollution for our environment etc.

• Acidic cleaning agents

The acidic cleaning agents generally included Sulfuric acid, nitric acid, phosphoric acid and various organic acids. Please do not use hydrochloric acid that could etch the stainless steel. The acid could remove the beer stone etc. Generally the diluted nitric acid or phosphoric acid (0.5-1%).

The organic acids with a lower corrosion compared with nitric acid. They are environmental cleaning agents, but with higher cost.

• Alkaline cleaning agents

The common used ones are Sodium hydroxide and Sodium phosphate.

Sodium Hydroxide is a kind of strong base that can be a solid, liquid. It is basis of most of the cleaning agents and with a strong corrosion resistance. It is the basis for most of the cleaning agents,generally the fortified concentration at about 1.5-2%, and with sterilization function in the mean time. The sodium hydroxide liquid could be added with surfactant, that will reduce the surface tension of water and infiltrate the dirt, then make it fall off.

Sodium phosphate  Its aqueous solution is alkaline and could etch the aluminum and stannum. It is not good for our environment as it included phosphorus.