How do yeast function in the fermentation process concerning acetaldehyde?

Yeast plays a crucial role in the fermentation process by taking up acetaldehyde, a compound that can be a byproduct of fermentation. As yeast metabolizes sugars during fermentation, it may produce acetaldehyde as an intermediary product. However, a vital function of yeast is to further process this acetaldehyde, converting it into ethanol and other compounds that are more beneficial to the final beer product.

This processing helps to reduce the concentration of acetaldehyde in the finished beer, as high levels of acetaldehyde can impart undesirable flavors reminiscent of green apples or raw cucumbers. By reabsorbing and processing acetaldehyde, yeast directly contributes to the overall flavor profile and quality of the beer, ensuring that the final product is balanced and pleasant to drink.

The other options do not accurately reflect the role of yeast in handling acetaldehyde during fermentation.