Why does our whipped cream collapse on standing

During the whipping of cream the movement of the wires of the whisk through the fluid draw in small bubbles of air. Fat chains in the cream form at the interface of the air bubble and the aqueous phase, where they stabilise the bubbles and prevent them from rising and escaping from the cream after mixing. In the stable foam that is formed the liquid of the aqueous phase is effectively trapped in the spaces between the stablised air bubbles. On standing, the bubbles in the cream become unstable and they collapse. In doing so the liquid previously held in the spaces between the bubbles now escapes and usually drains under the influence of gravity.

The rate at which the cream will collapse depends on the many factors that affect the stability of the foam. Since the main stabilising agent is the fat present there needs to be a minimum of 40% butterfat in order to produce a stable foam structure. The stabilising effect of the fat may be supplemented with other suitable stabilising agents (see 12.25).

The amount of stabilising material present limits the maximum amount of air that can be beaten into the cream. This is because the stabiliser must be located at the bubble surface. The greater the quantity of air incorporated into the batter, the larger the surface area that needs to be stabilised. With ever-increasing quantities of air being incorporated a point is reached when the stabiliser cannot stretch any further and the cream density stops falling.

Too much air in the cream will make it unstable and more likely to collapse with small changes in storage conditions, e.g. a small increase in temperature can cause the air to expand and increase the surface area that must be covered by the stabiliser. The aeration of cream may be expressed as relative density or specific gravity (see 13.4). It is also common to see cream aeration expressed as 'overrun'. This is the reciprocal of density expressed as a percentage (thus a relative density of 0.77 = 130% overrun).

Careful control of cream temperature before during and after whipping needs to be taken. Before whipping ensure that the cream temperature is 3-5 °C (38-40 °F). If for any reason the cream temperature is above this, chill it in a refrigerator until its temperature has fallen to this level to increase the proportion of solid fat. During warm weather in particular, rinse out the bowl and beater with cold or chilled water, or preferably place in a refrigerator for some time before use.

Whisk the cream on a medium speed until it starts to thicken, then finish whisking on high speed. During warm weather the cream should be whisked in as short a period as possible to minimise the time it is exposed to the high atmospheric temperature. Aim to have the whisked cream at a maximum temperature of 10 °C (50 °F) at the end of whisking. After whipping, the bulk of the cream should be stored in a refrigerator at 3-5 °C (38-40 °F) and after depositing the cream temperature should not be allowed to exceed 10 °C (50 °F). Above this temperature the cream will start to collapse.

If attention to the cream temperature control is not enough to overcome the problem, then we suggest increasing the butterfat content to about 42%. If your supplier is unable to provide this you could blend six parts by weight of whipping cream containing 40% butterfat with two parts by weight of double cream containing 48% butterfat.

It is not uncommon to experience whipping problems with fresh cream arising from changes in the diet of cows. In the UK the so-called 'spring flush' problem with diary cream arises when cows move from winter feed to spring grass and the composition of the fats in the cream may change (Bent, 1998).

Reference

BENT, A.J. (1998) Speciality fermented products, in Technology of Breadmaking (eds S.P. Cauvain and L.S. Young), Blackie Academic & Professional, London, UK, pp. 214-239.

Continue reading here: Recently we experienced a problem with a fishy taint in a batch of buttercream

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