Effects on yeast Flashcards
What are some compounds that affect yeast?
Zinc (Zn2+), calcium (Ca2+), magnesium (Mg2+), manganese (Mn2+), copper (Cu2+), iron (Fe2+), potassium (K+)
These compounds act mainly as co-factors for yeast enzymes.
What is the role of co-factors in enzymatic reactions?
Co-factors help enzymes catalyse reactions but cannot do so on their own.
Co-factors are essential for the proper functioning of enzymes.
What is the importance of calcium for yeast?
Calcium is essential for yeast flocculation and promotes the binding of yeast cells.
This binding helps clarify the beer by removing suspended yeast.
How can a lack of required compounds affect yeast?
It can negatively affect yeast’s metabolic pathways, causing off-flavours, reduced ethanol production, and poor yeast crops.
Proper mineral balance is crucial for optimal yeast performance.
What does colloidal stability refer to in beer?
Colloidal stability refers to the presence of haze in the beer.
A colloidal system involves one substance suspended in another, affecting beer clarity.
What indicates high colloidal stability in beer?
High colloidal stability means that the beer has no haze.
Low colloidal stability suggests that the beer is hazy.
How does calcium contribute to beer clarity?
Calcium promotes yeast flocculation, helping to remove yeast suspended within the wort/beer.
This process clarifies the beer.
What is ‘hot break’ and how is it formed?
‘Hot break’ is formed by the interaction of calcium and magnesium with proteins and polyphenols, improving wort clarification.
This process is essential during the wort boiling stage.
What is the effect of calcium reacting with oxalate?
Calcium reacts with oxalate to form calcium oxalate, which precipitates out, improving wort clarity and preventing gushing.
Gushing refers to uncontrolled over-foaming of beer.
What negative effects do copper and iron have on beer?
Copper and iron act as oxidation catalysts, which can negatively affect colloidal stability.
Oxidation can lead to undesirable flavours and haze.
How does silicate affect beer clarity?
Silicate can cause haze when bound to calcium and negatively affect wort run-off separation.
This results in a more turbid wort and ultimately affects wort clarity.
What can varying mineral levels impact in beer?
Varying mineral levels can impact the taste profile of the beer.
Knowledge on alkalinity is essential for adjusting product water to support flavour profiles.
