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globules (less than 1 mm). Separation efficiency is

influenced by the geometry of the disks (angle, diam-

eter, etc.), their distance apart, and the rotational

speed of the bowl. However, there are practical limits

to these parameters, and little improvement is made

even with very high rotational speeds. A commercial

separator would normally work at between 4500 and

6000 rev min

1

, depending on size, to give cream

with a fat content of approximately 40% and skim

milk with a fat content of 0.06%. Incorporation of air

markedly reduces the separation efficiency. Hermetic

or hydrohermetic sealing systems are used to minim-

ize air incorporation. Milk is fed into a hermetic

separator through a hollow drive spindle. The cream

and the skim milk are removed by rotating pumps in

their respective chambers. The milk attains the rota-

tional speed of the bowl more gradually in the her-

metic separator when compared with the paring disk

separator where the milk attains the rotational speed

of the bowl almost instantaeously. The absence of air

and the gentle action of the hermetic separator result

in less free fat in the cream than with a paring disk

separator.

0007 The fat content of the cream is controlled by the

relative flows of the outlet streams. If the flow of

cream is restricted, the fat content will increase, but

the separation efficiency will decrease if the fat con-

tent becomes very high. The separation temperature

also influences the separation efficiency due to the

effects on the cream viscosity and the relative dens-

ities of the fat and the serum. However, higher tem-

peratures may disrupt the membrane, resulting in

more free fat in the cream. Phospholipids migrate

from the membrane into the serum as the temperature

increases; this affects the functional properties of the

cream, notably whipping, which may be adversely

affected. Optimum separation of milk is normally

achieved at 52–55



C, but some separators are

designed to separate milk at around 5



C, the tem-

perature at which it reaches the processing facility.

Such separators have wider gaps between the disks

than conventional separators to cope with the more

viscous cream. Cold milk separators are always of

fully hermetic design. The separation efficiency is not

as good as with conventional separators, and there is

a greater chance of damaging the fat globule mem-

brane with a high proportion of solid fat in the cream.

0008 Cream is normally standardized continuously by

automatic control of the various streams. The fat

content of the cream can be monitored through rapid

instrumental analysis or by in-line density measure-

ment, and the resultant signals may be used by pro-

cess logic controllers (PLCs) to adjust the back

pressures in the product lines automatically, in order

to control the fat contents.

Pasteurization, Sterilization, and Packaging

0009Cream may be batch-pasteurized at a temperature of

63–65



C and a holding time of approximately

30 min. Continuous pasteurization in a plate heat

exchanger and holding tube is more common. Al-

though 72



C for 15 s is the legal minimum for

milk pasteurization in most countries, the US Food

and Drug Administration (FDA) recommends that

equivalent heat treatment can be achieved for creams

with fat contents >10% by increasing the pasteuriza-

tion temperature by 3



C at any given holding time.

This recommendation has been incorporated into the

New Zealand dairy industry pasteurization standard

for cream, with the proviso that the minimum holding

time at temperatures greater than 84.7



C is set at

1 s to give an adequate safety margin. The time/

temperature relationship for cream pasteurization at

temperatures below 84.7



C can be expressed as:

log t ¼ð14885=ðT þ 276:1ÞÞ  41:97,

where t ¼ minimum holding time (s); T ¼ minimum

temperature (



C).

0010Temperatures above 80



C can shorten the shelf-life

of the cream, possibly through the activation of bac-

terial spores. It is important that the cream is handled

with care during any processing; positive pumps are

recommended to avoid disruption of the fat globule

membrane and the release of free fat. Pasteurized

cream can be packed in glass, cartons, or plastic pots.

Cartons require a water-tight barrier between the

cardboard and the cream, and polyethylene is almost

universally used, having replaced wax. Pots can be

made of polystyrene or polypropylene, the latter

being more popular. Covers can be aluminum foil/

plastic laminates that are heat-sealed on to the top

of the containers with a snap-on cover, or they can be

screw-on plastic tops, normally with a tamper-proof

plastic ring.

0011Alternatively, the cream can be in-can-sterilized for

extended shelf-life. The cream, which must be of low

bacterial count and low acidity, is standardized to a

fat content close to 23%, which represents the legal

minimum in many countries. Such cream is often

called ‘reduced cream.’ The cream is preheated and

homogenized. Homogenization breaks the large fat

globules into smaller globules to reduce the tendency

for the fat globules to rise (cream), at the same time

creating a more stable fat globule membrane as pro-

tein is adsorbed from the serum to cover the new fat/

serum interface. To obtain a final product without

graininess, it may be necessary to add stabilizing

salts, such as trisodium citrate, a sodium phosphate,

or sodium carbonate, which increase the availability

of serum casein due to calcium sequestration and/or

1686 CREAM/Types of Cream

an increase in pH. Other stabilizers, such as carra-

geenan or sodium alginate, may also be added to

enhance the stability and inhibit the separation and

syneresis during storage of the processed cream. The

cream is filled into lacquered cans that are sealed and

sterilized in a suitable retort or continuous sterilizer.

Conditions for sterilization are normally 115–120



for 10–20 min. Holding times depend on the size

of the can and whether agitation is applied during

retorting. The high viscosity of the cream reduces

heat transfer, and the volume of a can is restricted

(<300 ml) as the prolonged heat treatment necessary

for larger volumes would increase Maillard browning

reactions between protein and lactose, and adversely

affect the color and flavor. The heat treatment does

have an adverse effect on the stability of the cream,

and some agglomeration of fat globules does occur

(Figure 4).

0012 Cream may be UHT-sterilized (140



C for 2s)

and aseptically packed. The aseptic packaging mater-

ial includes laminated cartons with plastic (e.g., poly-

ethylene) on the inside, an intermediate aluminum

foil barrier, and cardboard on the outside. The cartons

may be preformed or formed continuously from a roll

of laminate. The material must be first sterilized with

hydrogen peroxide and the residual sterilant removed

by draining and heating before filling. Pack sizes

range from 100 ml to 1 l. Plastic pots may also be

used, thermoformed continuously from a sheet before

aseptic filling in a laminar filtered airflow and final

heat sealing of an aluminum foil/plastic laminate on

top of the pot. Pack sizes range from about 10 ml

(single serve coffee cream) to 1 l. Lacquered metal

cans are used for UHT aerosol cream.

0013 Cream is packed in bulk in plastic pouches or

plastic/foil laminate pouches contained in cartons or

returnable plastic crates. UHT cream may be packed

in bulk using special aseptic filling systems. Volumes

up to 1000 l can be packaged, but bulk packaged

cream would normally be retailed in packs of 5–25 l.

0014Cream is susceptible to deterioration because of

microbial, enzymatic, and physicochemical changes.

Pasteurized cream has a limited shelf-life of a few

days and must be kept chilled (< 5



C). Although

microbial deterioration is the major hazard, lipases

in the cream release fatty acids, which can result in

rancid flavors. The fat globules will tend to rise to the

surface and agglomerate unless the cream is hom-

ogenized. Homogenization is advantageous for

low fat creams to increase the viscosity and inhibit

creaming. Storage at a low temperature retards the

‘plugging’ of nonhomogenized cream as creaming is

retarded due to the higher viscosity, and the lower

proportion of liquid fat in the globules minimizes

agglomeration. Cream in transparent containers

should be kept in the dark, as light will cause photo-

induced oxidative changes in the milkfat, with

consequent deterioration in flavor. The shelf-life of

sterilized cream is limited by chemical and physical

changes. Spore-forming organisms may be a problem

if not killed by preheating. In-can-sterilized cream has

a long shelf-life at ambient temperature, although

Maillard reactions, which are initiated in the steriliza-

tion process, and serum separation (syneresis) may

occur during storage. The greatest problem with

UHT cream is physical separation of the fat with

subsequent agglomeration, although this can be min-

imized by homogenization. The addition of sodium

caseinate or gum stabilizers, such as carrageenan or

sodium alginate, will also inhibit the agglomeration

of fat globules. Psychrotrophic bacteria in the milk

may release heat-resistant proteolytic enzymes, which

will result in coagulation and bitter flavors. The

shelf-life of UHT cream is limited to some extent by

0.1 1.0 10.0 100.0

Particle diameter (µm)

Volume (%)

fig0004 Figure 4 Particle size distribution in an in-can-sterilized cream.

CREAM/Types of Cream 1687

its packaging. Plastics are permeable to air, and con-

sequent oxidation adversely affects the flavor. A layer

of aluminum foil in a laminate will prevent oxygen

entry, but the flavor will still deteriorate due to non-

oxidative reactions.

Freezing of Cream

0015 Freezing of cream will provide protection against

microbial deterioration. However, unless the freezing

is very rapid, large ice crystals will disrupt the emul-

sion, resulting in separation on thawing. Bulk frozen

cream is used for manufacturing purposes when

phase separation is not important or a homogeniza-

tion step is included. Sometimes, cream is frozen at

times of the season when production is high. This

cream can be used subsequently for butter production

when stocks of fresh cream are insufficient to meet

market demands. Bulk frozen cream may be used for

the production of cream soups or ice cream.

0016 If cream is frozen rapidly, small ice crystals that do

not disrupt the emulsion are formed. One commercial

process includes the use of a frozen novelty machine

that forms thin rods of frozen cream. Another com-

mercial process uses two continuous stainless steel

belts that form a continuous film of frozen cream

that breaks into flakes. Alternatively, cryogenic freez-

ing with liquid nitrogen may be used. Frozen cream

must be stored at less than 18



C for a long shelf-

life; temperature cycling must be avoided as this will

result in the formation of large ice crystals that will

damage the fat globule membranes.

Uses of Cream

Cultured (Sour) Cream

0017 Cream can be cultured with suitable organisms that

metabolize lactose to lactic acid and also provide

other flavoring compounds. The reduction of pH

coagulates the protein, which thickens the product

and gives a somewhat extended shelf-life when kept

under refrigeration. Pasteurized single cream (ap-

proximately 18% fat) is normally used as the starting

material for culturing. Cre

me fraı

che is a higher fat

product that is lightly fermented. Sour cream is used

as an ingredient in many savoury foods (e.g., strogan-

off, vegetable dishes, dressings, snack dips, etc.).

Coffee Cream

0018 Cream is a favorite ‘whitening’ agent for coffee as it

provides a pleasant texture and flavor to complement

the coffee flavor. Long-life coffee creamers can be

produced by sterilization (UHT) or by drying. UHT

coffee creamers are normally low-fat (10–15%)

creams that are given an extensive homogenization

(Figure 5). The particle size distribution shows a

cream with all fat globules less than 2 mm in diameter.

The heat and acidity of coffee provide a hostile envir-

onment for the cream, and destabilization of the

emulsion can result in ‘feathering,’ with curdled

cream forming a characteristic pattern on the surface

of the coffee. The presence of calcium in the cream

enhances the incidence of feathering, and the presence

of calcium-sequestering agents, such as trisodium cit-

rate or sodium phosphates, helps to alleviate this.

Feathering may develop with time of storage of the

coffee cream as calcium migrates from the serum to

the fat globule membrane. Extra protein in the form

of sodium caseinate will help to stabilize the cream

against feathering. UHT coffee creams are most often

packaged in single-serve form-fill-seal containers of

about 15 ml.

0019Cream can be dried to form a powdered coffee

creamer. Products available on the market are nor-

mally recombined products based on vegetable fat

(coffee whiteners).

Whipped Cream

0020Mechanical agitation of cream will introduce air into

the cream as dispersed bubbles. The protein in the

cream provides stability for the formation of a foam.

The fat globules concentrate at the air/serum inter-

face, where the surface tension is believed to disrupt

the fat globule membrane. As agitation continues, the

air bubbles become smaller, and the globules interact

to form a stable network (Figure 6). The interaction

depends on several factors. The fat content has to be

sufficiently high (approximately > 28%) to give the

necessary density of globules at the interface. The

membrane around the fat must not be too stable, as

some mechanical breakdown is necessary to develop

the interaction and ‘welding’ of the globules. Hom-

ogenization has an inhibitory effect on whipping. The

temperature and the aging of the cream are import-

ant. If the temperature is above 10



C, excessive

0.1 1.0 10.0

Particle diameter (µm)

Volume (%)

fig0005Figure 5 Particle size distribution in a UHT coffee cream.

1688 CREAM/Types of Cream

liquid fat will weaken the structure and act as a foam

depressant. Cream should be stored refrigerated for at

least 12 h before whipping to optimize fat crystalliza-

tion and membrane destabilization. Long-life whip-

ping cream can be produced by UHT treatment. Some

homogenization is necessary to prevent ‘creaming’

and consequent superficial agglomeration of the

cream. The whipping time of UHT cream is thus

generally longer than that of normal non-

homogenized cream. To give stability during storage,

addition of gum stabilizers, such as carrageenan,

helps to prevent the association and agglomeration

of the fat globules. Whipping properties can be

improved by the addition of emulsifiers. Emulsifiers

can provide extra surface activity and increase over-

run (percentage increase in the volume of the liquid

cream when converted to whipped cream). Some

emulsifiers (e.g., polysorbates) will increase fat glob-

ule interactions during whipping and consequently

reduce the whip time and give a stiffer whip. The

shelf-life of UHT whipping cream is considerably

extended by refrigerated storage. Temperatures

>25



C and temperature cycling are particularly dele-

terious to the cream properties. Aerosol cream is

packed under pressure with nitrous oxide gas. When

the dispenser is activated, the cream is forced out of

(b)

(a)

20 µm

fig0006 Figure 6 Confocal images of (a) unwhipped cream and (b) whipped cream (dark objects are air cells).

CREAM/Types of Cream 1689

the can by gas pressure, and the foam structure is then

formed by the expanding gas that was dissolved in the

cream. The percentage increase in volume (overrun)

of aerosol cream (400–500%) is much greater than

that of normal whipped cream (approximately

100%). As a result, the stability of the foamed aerosol

cream is not as great as that of normal mechanically

whipped cream, but the interaction of the fat globules

is still important in providing stability.

0021 The major industrial use of cream is as whipped

cream in baking and confectionery to decorate cakes

and desserts. Whipped cream can be produced com-

mercially in large batch mixers or in continuous

machines (Figure 7).

0022 Control of cream whipping is very important as

‘overwhipping’ will result in the complete breakdown

of the emulsion with ‘churning’ of the fat and release

of free serum. ‘Underwhipping’ will give a soft foam

without adequate structure to hold its shape. As

whipped cream has a better freeze–thaw stability

than the unwhipped product, it can be incorporated

successfully in frozen confections. The addition of

stabilizer, such as carrageenan or sodium alginate,

will reduce the tendency of the whipped product to

synerese.

Cream Liqueurs

0023 Cream liqueurs are popular beverages that use the

preservative powers of alcohol for a long shelf-life.

Typically, the liqueurs contain 15% fat from the

cream, 19% sucrose, and 14% alcohol. Higher-proof

products contain 10% fat and 19% alcohol. Emulsi-

fication and emulsion stability are provided by

sodium caseinate with a fat:caseinate ratio of 1:5,

i.e., 3% caseinate in standard liqueurs and 2%

caseinate in high-proof liqueurs. Other emulsifiers

may be added (e.g., glycerol monostearate (GMS) at

0.34%) to give extra emulsion stability. The most

common form of destabilization was found to be

calcium-induced aggregation of fat globules, so

sodium citrate was introduced into the formula at a

level of approximately 0.16% to sequester free cal-

cium in the serum of the liqueur. Some care is required

in the use of the citrate as calcium citrate crystals may

precipitate from the liqueur if used in excess. The

liqueurs are manufactured by dispersing the sodium

caseinate and sodium citrate in water, adding the

cream and GMS to give a cream base. Ethanol and

dissolved sucrose are then added to form a preemul-

sion that is homogenized to give the final product.

The mixing and homogenization are conducted at

approximately 55



C. The ethanol can come from a

variety of spirits, and flavors are added to differen-

tiate individual brands of product. Extensive hom-

ogenization (e.g., twice at 17.5 MPa and twice at

4 MPa) assists in yielding a stable emulsion. Lack of

sufficient homogenization can lead to formation of a

‘neck plug’ of aggregated fat during storage.

Other Uses of Cream

0024Cream is the raw material for the production of

butter and anhydrous milkfat (AMF). In New

Zealand, where cows are pasture-fed, cream for

buttermaking is routinely steam-stripped and

vacuum-treated during pasteurization. This reduces

volatile flavor components from the pasture to desir-

able levels in the final products.

0025The Vacreator

(Figure 8) has long been the equip-

ment of choice for cream treatment in New Zealand,

but is now being superseded by the Flavourtech

spinning cone column (Figure 9). In both the Flavour-

tech

and the Vacreator

, steam is injected counter

to the flow of cream, and then the vapors and liquid

cream are separated under vacuum. The Flavour-

tech

has a series of fixed and spinning cones

that expose the cream to the steam over a large sur-

face area for more effective stripping of the volatile

components.

Refrigerant

Vessel

Air valve

Pump

Static mixer

Product

Mechanical whipper

Product

Refrigerant

Pump

Metered

air

Refrigerant

fig0007 Figure 7 Continuous cream whippers.

1690 CREAM/Types of Cream

0026 Cream can be used as a source of milkfat in foods.

It contains more flavor components than butter or

AMF. Fresh cream is generally regarded as being the

optimum milkfat source for best-quality icecream.

0027 Cream can be dried to produce high-fat powders

that may be used as ingredients in foods and may be

particularly useful for dry blends (e.g., cake mixes,

soup mixes, or icecream powders). The spray drying

of cream demands formulations to suit the end use

and special driers are required to handle the high-fat

product. Cream powders are not produced in large

quantities because vegetable-fat-based products are

much cheaper and easier to produce. Cream-based

powders have the advantage of a superior flavor, but

protection against lipid oxidation is required to give

the product adequate shelf-life.

Vacuum

vessel 1

−0.07 bar

98⬚C

Vacuum

vessel 2

−0.2 bar

94 ⬚C

Vacuum

vessel 3

−0.2 bar

94 ⬚C

Vacuum

vessel 4

−0.3 bar

89 ⬚C

Sight

glass

Steam

Baffle

valve

Preheater

Raw

cream in

Cream

out

Spent

vapor

Two-stage

ejector

condenser

Condenser

water

Vacuum

vessel 5

−0.84 to −0.80 bar

55−60 ⬚C

Cream flow

Steam and vapor flow

Internal cream pump

fig0008 Figure 8 Vacreator

Liquid/slurry

inlet

Vapor plus

volatiles

outlet

Gas/vapor

inlet

Liquid

outlet

Pulley

for drive

belt

Stationary

cone

Spinning

cone

Spinning cone

shaft

Spinning

cone

shaft

Upward

vapor

flow

Downward

liquid

flow

Liquid &vapor

Mixing

fig0009 Figure 9 Flavourtech

spinning cone column. From Flavourtech Pty. Ltd., Sydney, Australia, with permission.

CREAM/Types of Cream 1691

See also: Butter: The Product and its Manufacture;

Colloids and Emulsions; Freezing: Cryogenic Freezing;

Heat Treatment: Ultra-high Temperature (UHT)

Treatments; Ice Cream: Methods of Manufacture;

Properties and Analysis; Lactic Acid Bacteria; Liqueurs:

Cream Liqueurs; Oxidation of Food Components;

Packaging: Packaging of Liquids; Pasteurization:

Principles; Pasteurization of Liquid Products; Separation

and Clarification; Stabilizers: Applications;

Sterilization of Foods; Storage Stability: Mechanisms

of Degradation

Further Reading

Anderson M and Brooker BE (1988) Dairy foams. In:

Dickinson E and Stainsby G (eds) Advances in Food

Emulsions and Foams, pp. 221–255. London: Elsevier

Applied Science.

Bird J (1991) Cream separation. Journal of the Society of

Dairy Technology 44: 61–63.

Buchheim W and Dejmek P (1997) Milk and dairy-type

emulsions. In: Friberg SE and Larsson K (eds) Food

Emulsions, 3rd edn. pp. 235–278. New York: Marcel

Dekker.

International Dairy Federation (1992) Monograph on the

Pasteurization of Cream. Bulletin of the International

Dairy Federation No. 271. Brussels: International Dairy

Federation.

International Dairy Federation (1996) UHT Cream. Bul-

letin of the International Dairy Federation No. 315,

pp. 3–34. Brussels: International Dairy Federation.

Keenan TW and Dylewski DP (1995) Intracellular origin

of milk lipid globules and the nature and structure of the

milk lipid globule membrane. In: Fox PF (ed.) Advanced

Dairy Chemistry, Lipids, 2nd edn, vol. 2, pp. 89–130.

London: Chapman & Hall.

Lehmann HR and Zettier K-H (1994) Separators for the Dairy

Industry, Technical Scientific Documentation No. 7,4th

revisededn.Oelde,Germany:WestfaliaSeparatorAG.

Lynch AG and Mulvihill DM (1997) Effect of sodium case-

iante on the stability of cream liqueurs. International

Journal of Dairy Technology 50: 1–7.

Muir DD (1989) Cream liqueurs. Journal of the Society of

Dairy Technology 42: 31.

Mulder H and Walstra P (1974) The Milk Fat Globule.

Emulsion Science as Applied to Milk Products and Com-

parable Foods. Wallingford, UK: CAB International/

Wageningen, The Netherlands: PUDOC.

New Zealand Dairy Board (1999) NZCP 7: Pasteurisation

Equipment and Instrumentation Code of Practice.

Wellington: New Zealand Dairy Board.

Rothwell J (ed.) (1989) Cream Processing Manual, 2nd edn.

Huntingdon, UK: The Society of Dairy Technology.

Towler C (1994) Developments in cream separation and

processing. In: Robinson R K (ed.) Modern Dairy Tech-

nology, Advances in Milk Processing, 2nd edn. vol. 1,

pp. 61–105. London: Chapman & Hall.

Walstra P (1995) Physical chemistry of milk fat globules. In:

Fox PF (ed.), Advanced Dairy Chemistry, Lipids, 2nd

edn. vol. 2, pp. 131–178. London: Chapman & Hall.

Clotted Cream

S Jolley, Otaihanga, Paraparaumu, New Zealand

History

0001Clotted, or scalded, cream is made principally in the

West Country of England, in the counties of Devon,

Cornwall, and Somerset. The process dates back a

couple of centuries to a time when these counties

were a long and difficult journey from the main con-

sumers of milk in the cities, well before the invention

of the mechanical cream separator. Clotted cream

was made originally on farms rearing and fattening

cattle, where it was found that skimmed milk was

more easily digested by young calves than rich full-

cream milk, and if the remaining cream was heated, it

kept longer and had a pleasant flavor.

0002The predominant cattle breeds in the area at the

time, Jersey, Guernsey, Devon, and South Devon,

produced milk of a high fat percentage, with large

fat globules that rose to the surface in a thick, firm

cream layer. Milk was left to stand in shallow setting

pans overnight, for up to 24 h, and heated slowly the

next day for 2–3 h until the surface became wrinkled

but unbroken, and bubbles appeared just below the

surface. It is at this stage that the characteristic flavor

developed. Originally, the cream was heated on a

tripod over the fire in an open hearth and later on

a kitchen range.

0003The pan was then moved to a cool place allowing

the cream to cool slowly and form the deep yellow

crust while the body of the cream thickened. The

cream was then skimmed off using flat perforated

skimmers.

0004The advent of small hand-driven mechanical separ-

ators for farm use simplified the whole process. Milk

straight from the cow could be run through the separ-

ator, the warm milk at about 35



C being the right

temperature for efficient separation, and the cream

scalded immediately. The separated cream was often

floated on a small amount of skim for scalding on the

stove, to avoid scorching the bottom of the cream layer.

0005At a later stage, scalding was more likely to take

place in a piece of equipment like a bain marie.The

setting pan containing the cream fitted into an aperture

on the top of a water bath, allowing the base and sides

of the pan to sit in the hot water circulating underneath.

The Product Today – Craft or Science

0006Clotted cream is still made on many farms in the

West Country and on a commercial scale in several

creameries, but little is made elsewhere. The area is a

1692 CREAM/Clotted Cream

well-known tourist destination, with Devonshire and

Cornish clotted cream teas a specialty, famous

throughout the world. One or two small manufactur-

ers in New Zealand, Australia, the USA, and Canada

cater for their local market.

0007 Although there remain many Channel Island and

Devon cattle in the West Country, much of the milk is

now produced by Friesians and other breeds of cow

the milk of which is whiter, with a lower fat percent-

age and smaller fat globules. This factor has an effect

on both color and texture of the final product, as do

the quality of pasture fed and the use of concentrated

feeds. For those producing clotted cream all year

round, there is the additional complication of sea-

sonal differences in fat composition, requiring adjust-

ments in the time/temperature combinations used in

manufacture to achieve a consistent final product.

0008 Clotted cream is a seasonal product, time-

consuming and labor-intensive to make, so commer-

cial enterprises are usually privately owned dairies

making clotted cream on a small scale and having

the capacity to increase production during the season.

It is also a luxury product and will never have a very

large market share, so expensive research time cannot

be justified to improve manufacturing methods. Any

developments in manufacture are largely individual

to suit the milk supply of the operation, the experi-

ence of the manufacturer, and, ultimately, their cus-

tomers. No two farm or factory operations are the

same, and details of the process will vary in each case.

0009 The traditional product has a sweet, nutty flavor,

with a golden crust of grainy texture and a body of

cream that is thick, smooth, and deep cream in color.

Related products are made commercially for the con-

fectionery trade. Apart from its use in the traditional

Devonshire or Cornish cream tea, when it is served

with scones or splits (light bread rolls) and strawberry

jam, clotted cream can be used on raw fruit, particu-

larly strawberries and raspberries; hot and cold des-

serts; in savory situations such as on quiches and with

baked potatoes; and in many dishes such as sauces

and curries, where it adds a rich, full flavor all its

own. Although limited quantities are sent from the

West Country to cities and catering establishments

throughout the country, most is sold locally.

Methods of Manufacture

Farmhouse Production

0010 Farmers who sell clotted cream as a lucrative sideline,

usually separate the milk to a fat content of 55–60%

as it leaves the parlor, using a small-scale centrifugal

separator, either electrically or mechanically oper-

ated. The cream is poured into large stainless steel

trays, usually rectangular in shape, for the heating

process. If the cream is for sale to retail outlets, it

can be poured directly into retail containers, provided

that they are manufactured to withstand the heating

process.

0011Heating is carried out by one of two methods. The

following times and temperatures are only guides.

Each operator will have to judge by the results until

the most suitable combination is achieved.

0012Forced-air convection oven: The trays or retail

containers are placed in the oven at 90



C for 50–

60 min. Initial cooling stages can be carried out in

the oven by turning off the heat but allowing the

fan to continue to run for up to an hour. Contain-

ers are then transferred to a cooling room or re-

frigerator to finish cooling, taking care not to

shake the cream and disturb the crust. Some oper-

ators move the cream to a cold room or refriger-

ator immediately after heating, but if the cream is

cooled too rapidly, the crust will collapse.

0013Scalding in a bain marie-type apparatus circulating

hot water: The scalder usually consists of a shallow

open-topped water container on a free-standing

frame, in which hot water at 90–95



C is circu-

lated. The stainless steel top can be designed to

take different sized trays or tubs for retailing. The

trays containing the cream, or racks holding pots,

are set into the covering top of the apparatus, so

that hot water is in contact with the sides and bases

of the containers. The cream is heated to 77–88



for 45–50 min. After heating, the trays are trans-

ferred to a cool room for cooling.

0014In either case, the essentials of the process are:

0015cream should not be more than 50 mm deep in the

container to ensure even heating;

0016air must be able to circulate freely above the con-

tainers to allow evaporation to form the crust;

0017the temperature/time combination must be high

enough to kill milk-souring organisms and prevent

off-flavors;

0018the heating temperature and time must be sufficient

to develop the flavor and texture, and form the

crust;

0019the cream should not be disturbed during process-

ing to allow the crust to form;

0020postheating contamination must be avoided;

0021cooling must be done slowly to achieve flavor de-

velopment, even thickening, and avoid the crust

collapsing, particularly in retail containers.

The criteria on which to judge the results are:

0022a rich, golden-colored crust that is wrinkled but not

broken, with a grainy texture when cold;

CREAM/Clotted Cream 1693

.0023 the body of cream that is smooth, thick, i.e. of

spreadable consistency, but not solid, a deep

creamy color, and with no separation of liquid at

the bottom of the container;

0024 a full, rich, creamy flavor that is nutty, sweet, and

lightly caramelized;

0025 a legal minimum fat percentage of 55%.

Commercial Manufacture

0026 Commercial-scale manufacture has adopted and de-

veloped the traditional methods by employing

modern technology. Milk destined for clotted cream

is separated using a centrifugal separator at a tem-

perature ranging from 35 to 40



C, to a fat content of

55–60%. This fat percentage may have to be adjusted

during the season as the composition of the butterfat

varies, in order to achieve a consistent viscosity in the

final product. Separation at this high fat percentage

can result in the loss of fat in the skim if a higher

separation temperature is used, which will drastically

affect the yield of product. The yield will also be

affected by evaporation from the cream surface

during scalding. Evaporation is necessary for the for-

mation of a good crust, but some operators may try to

restrict evaporation and loss of yield at the expense

of the crust.

0027 Most commercial operations pasteurize the cream,

many using plate-heat exchangers, but small dairies

may still use batch pasteurizers. From the point of

view of product safety, this step would seem to be

unnecessary as the cream is heated to, and held at, a

higher temperature than that required for pasteuriza-

tion during the scalding or heating process. Also, the

shear to which the cream is subjected could affect the

setting time and thickness of the finished cream. Some

operators compensate for this by adding a small per-

centage of homogenized cream prior to heating.

0028 Commercial heating of the cream can be carried out

in hot air using a convection oven, or by an extension

of the hot-water scalding process. Some operators use

a mixture of both methods, depending on the con-

tainer and end result required. Either method can be

automated to a limited extent.

0029 Forced air convection ovens (see Figure 1) can be

obtained in a range of sizes from bench-top models to

large free-standing models, their capacities depending

on the size of containers in the batch of cream being

processed. They are convenient and safe, as they do

not involve the use of very hot water, and steam is not

emitted into the room. It is essentially a batch process,

although it would be interesting to see if a bakery

oven with a moving conveyor would work as well.

0030 Ovens are convenient for heating cream in retail

containers. Cream is poured into tubs or trays after

separation and placed on to racks or wire mesh

shelves. These can be either slotted directly into the

oven or fitted into a large mobile unit that can be

pushed into a freestanding oven. Heating times can

vary from 65



C for 40–45 min for the 21-g packs for

airline catering, to 90



C for 1 h for 227-g (8-oz.)

tubs. The depth of crust formed on the airline por-

tions is limited by their size, and there is a loss of

flavor when using the lower heating temperature.

0031A typical water scalding process (see Figure 2)

involves running the cream into containers ranging

from 113-g (4-oz.) tubs to large trays for catering

purposes holding 4.53 kg. The containers fit into

trays that are put into the scalding apparatus, as

described for the farmhouse method. Water at 95



is circulated for up to 70 min, after which time the

trays are lifted out for cooling (See Figure 3).

0032Some operators say they stir the cream for the first

10 min to ensure even heating, and variations in

scalder design include gabled covers above the trays

to avoid heat loss.

0033One operator has adopted a continuous method of

scalding in which the cream is filled into pans holding

1.5–2.25 kg of cream. The pans are passed through

fig0001Figure 1 Free-standing hot-air convection oven showing over-

head fans and a mobile rack on the left-hand side, which has

shelves for retail containers.

1694 CREAM/Clotted Cream

fig0002 Figure 2 Large bain marie-style scalder, designed with a gabled cover to avoid heat loss.

fig0003 Figure 3 Commercial operator transferring a tray of cream in retail tubs from the scalder to the cooling room.

CREAM/Clotted Cream 1695