The worst offender being butyric acid (butanoic acid). My guess is: 1. A cardboardy or metallic taste is caused by oxidation. Associated with extended holding periods of butter for several months or longer. The processes are generally considered to occur in three phases: an initiation or induction phase, a propagation phase, and a termination phase. Attributable to cream from cows grazing on slough grass, eating musty or moldy feed or drinking stagnant water. The cause is usually due to Streptococcus lactis in poorly cooled milk. Anyone else ever experienced something like this? Hydrolytic rancidity results in the formation of free fatty acids and soaps (salts of free fatty acids) and is caused by either the reaction of lipid and water in the presence of a catalyst or by the action of lipase enzymes. maltigenes in milk or cream. ALL RIGHTS RESERVED. Cows impart an odor and taste within 30 minutes of eating or breathing grass or corn silage, legume hay, or brewer's grains. Long before it reaches the point of growing mold, butter will go rancid and develop an off-putting taste and smell. Heat and light also increase the rate of this and other phases of lipid oxidation. soapy, baby-vomit, blue cheese). Most dry feeds (like hay or concentrates), silage, green alfalfa, and various grasses produce feed flavors in butter. Rancid butter becomes yellow to brown and the flavor becomes harsh. No amount of anti-fungals, vitamins, etc will stop the dirty sock/ feet/ cheese / rancid butter smell. Today, most cows eat pretty standardized diets, but the smell of the barn will affect flavors, as does the amount of time since the cows last ate. Chemical flavors can be cowy (ketosis), rancid, oxidized, sunlight, and medicinal. In the final, termination phase of lipid oxidation, relatively unreactive compounds are formed including hydrocarbons, aldehydes, and ketones. I had a tub of Land O'Lakes spreadable butter with canola oil, half the tub had already been used but haven't used it for a while, but it's been kept in the fridge and the expiration date was 8/3. The cowy or ketone flavor is the result of the animal suffering from ketosis. Sign up to discover your next favorite restaurant, recipe, or cookbook in the largest community of knowledgeable food enthusiasts. A sour-bitter taste is identifiable with rancidity (i.e. There appears to be a seasonal effect, with the months between July and September having the highest occurrences, and is also caused by stressed cows, and plumbing issued with the processing tanks. It can also be caused by excessive copper or iron in the water supply used to wash equipment or compensate for dirty milking equipment The off-flavor can sometimes be detected in raw milk, but more often is noticed in high fat products such as butter or vanilla ice cream. According to dietician and food nutrition educator Mary Saucier Choate, there is very little risk of butter becoming contaminated because of its low water and high salt content. Opening the packaging and using the same packaging to wrap it back and if the packaging feels oily on the outside means that your butter will be prone to contamination. Attributable to excessive or improper use of alkaline products to reduce the acidity of the cream before pasteurization. Before I answer this question, I want to know… How (on earth!) Rancidity and oxidation result from the degradation of milkfat. Also associated with vat pasteurization without adequate agitation. Attributable to the use of whey cream or the blending of cream and whey cream for buttermaking. You must lose all Gluten, and you MUST be very strict about this. If you are using a type of butter that you are used to and it smells differently than it usually does, I … In complex systems, the products of each of these phases will increase and decrease over time, making it difficult to quantitatively measure lipid oxidation. Many of the oxidation pathways are not entirely understood.