Views: 0 Author: Site Editor Publish Time: 2026-09-18 Origin: Site
Cooling yoghurt is not the same duty as cooling milk. After fermentation the product is acidic, viscous, shear-sensitive, and already carries the texture the consumer will judge. An SS316 gasketed plate heat exchanger is a common choice for this service because the plate pack can be opened for inspection and cleaning, the 316 stainless steel plate material resists the acidic product environment, and the channel geometry can be selected for a viscous, non-Newtonian fluid rather than for water.
At CSTHEATEXCHANGER, we design and manufacture custom plate heat exchangers and refrigeration heat-transfer equipment, supporting customers from requirement review and technical communication through product selection, drawing confirmation, manufacturing, inspection, and delivery, with OEM and ODM service worldwide. For a yoghurt cooling duty, we start from your process data — product temperatures, flow rate, viscosity behaviour, coolant circuit, design pressures, gasket compatibility, and installation envelope — and build the exchanger around that, not around a catalogue number.
A gasketed plate-and-frame heat exchanger transfers heat between the product and a coolant through thin corrugated plates, sealed by elastomer gaskets and held in a bolted frame. For yoghurt cooling, that construction offers three practical advantages:
The plate pack opens. Gaskets and plates can be separated for inspection and manual cleaning. Under US federal dairy plant regulations (7 CFR 58.128), plate-type heat exchangers must comply with the 3-A Sanitary Standards for plate-type heat exchangers for milk and milk products, all gaskets must be tight and kept in good operating order, and plates must be opened for inspection by the operator at sufficiently frequent intervals to confirm the equipment is clean and in satisfactory condition. A gasketed unit makes that inspection physically possible; a fully brazed unit does not.
SS316 suits an acidic product. Yoghurt is cooled after the pH has fallen. The same regulation requires product-contact surfaces of pasteurizers, coolers, and related equipment to be stainless steel or an equally corrosion-resistant material, kept free from cracks and corroded surfaces. 316 stainless steel is widely specified for product-contact plates in dairy service for its corrosion resistance relative to 304.
Channel geometry can be matched to a viscous product. Yoghurt does not behave like water. Plate pattern, channel gap, pass arrangement, and pressure-drop allowance must be selected for the actual product rheology so that the exchanger cools the yoghurt without excessive shear or unacceptable pressure loss.
CSTHEATEXCHANGER recommendation: treat gasket material selection and plate-pack access as primary specification items for a yoghurt duty — not as accessories chosen after the thermal calculation.
Published dairy science describes a clear sequence. Milk for yoghurt is typically given a high-temperature pasteurization — commonly 85 °C for 20 minutes, or 90–95 °C for 5 minutes — which denatures most whey proteins and strongly increases the viscosity and firmness of the finished yoghurt. Fermentation then develops the curd and flavour.
Cooling begins once the pH reaches approximately 4.7–4.3. The product is cooled to around 5 °C to inhibit starter-culture growth and metabolic activity and to stop the acidity from rising further. Two approaches are documented:
Cooling strategy | Described method | Documented texture outcome |
|---|---|---|
One-phase cooling | Rapid reduction of coagulum temperature to below 10 °C | Fermentation inhibited; yoghurt with lower viscosity |
Two-phase cooling | Rapid reduction to below 20 °C, then gradual cooling to 5 °C storage temperature | Increased viscosity and limited syneresis; common practice, particularly where fruit is added |
This matters for equipment specification: a two-phase strategy implies a first-stage cooler with a defined intermediate outlet temperature, and the plate heat exchanger duty must be stated for the stage it actually serves. Tell us which stage the exchanger is for, and the target inlet and outlet temperatures for that stage.
For set-type yoghurt fermented in the retail container, cooling occurs after packing and the heat exchanger duty applies to a different point in the line than for stirred or strained yoghurt, which is fermented in tanks under mild stirring. Confirm the product type when you send your enquiry.
At CSTHEATEXCHANGER, we build heat exchangers for a wide range of media — water, steam, refrigerant, glycol, ammonia, carbon dioxide and others — and we produce both standard commercial units and heavy industrial heat exchangers for process applications. Our plate heat exchanger work includes custom plate material and gasket selection, channel arrangement, connection configuration, and design-pressure definition based on the operating conditions of both circuits.
Our published custom plate heat exchanger enquiry framework covers exactly the categories a yoghurt cooling project needs:
Specification area | What we review |
|---|---|
Application and system | Equipment function, installation location, indoor/outdoor, available space, orientation and mounting, continuous or intermittent operation, delivery schedule |
Product / process side | Fluid type, concentration, inlet and outlet temperatures, flow rate or required capacity, pressure-drop limit, design pressure and temperature, cleanliness and suspended solids, corrosion or scaling conditions |
Coolant side | Fluid type — water, glycol solution, brine or refrigerant — concentration, temperatures, flow rate, pressure-drop limit, design pressure and temperature, freeze-protection requirements |
Thermal performance | Required capacity in kW, load profile, design operating point, minimum and maximum operating capacity, approach temperature, allowed outlet-temperature variation, performance margin, part-load conditions |
Plate and material | Plate material grade and standard, plate thickness, plate surface finish, wetted-component materials, connection materials, frame and clamping plate material, gasket material and compatibility, gasketed or brazed construction, corrosion allowance, material certificates |
Connections and mechanical | Connection sizes and types, orientation, centre-to-centre dimensions, flange/thread/welding standard, overall dimensional limits, weight limit, mounting and support, removable plate-pack requirement, service and cleaning access, drain and vent connections |
Pressure, temperature and safety | Maximum working pressure per circuit, hydrostatic test pressure, design temperature per circuit, operating range, differential pressure between circuits, vacuum conditions, applicable pressure-equipment regulations, inspection and certification, leak-test standard, safety factors |
Controls and operation | Capacity control, temperature and pressure sensors, flow monitoring, freeze protection, high/low pressure protection, alarms and shutdown, PLC or BMS integration, remote monitoring, start-up and shut-down sequence |
We evaluate both circuits independently, because the product side and the coolant side rarely share the same pressure and temperature conditions — and in a yoghurt duty they almost never do.
State the required stainless steel grade and material standard explicitly, and say whether you need material certificates. If your quality system or customer audit requires documented traceability for product-contact material, declare it at enquiry so it is inside the quoted scope rather than an afterthought.
Plate thickness affects pressure capability and mechanical robustness; surface finish affects cleanability and is frequently specified in sanitary applications. Both are on our enquiry checklist — provide your requirement, or tell us the standard you must satisfy and we will confirm what we can supply against it.
Specify whether the 316 requirement applies to the plates only or to all wetted components, including connections. Frame and clamping-plate material should be stated separately, since these are not product-contact surfaces in the same sense.
For dairy pasteurizing systems, the regenerator section is governed by a pressure-differential requirement so that any leak flows from the pasteurized side toward the raw side, and regulators monitor this closely. A yoghurt cooler downstream of fermentation is not a regenerator, but differential pressure between product and coolant is still a design input — it is on our enquiry list and should be stated with the design pressures for each circuit.
In a gasketed plate heat exchanger the gasket, not the plate, is usually the limiting component. For a yoghurt cooling duty, confirm:
Chemical compatibility with the acidic product at the actual pH and temperature
Compatibility with the CIP regime — caustic and acid cycle chemistry, concentration, temperature, and duration
Temperature limits for both the product side and any hot-water or sanitising cycle the unit will see
Attachment method — clip-on or glued — and its effect on regasketing time
Regasketing interval and spare-gasket availability, since gaskets are a planned consumable
Material compliance — under 7 CFR 58.128, non-metallic product-contact parts other than glass must comply with the 3-A Sanitary Standards for plastic or rubber and rubber-like materials
Send us the product pH range, the CIP chemistry and temperatures, and any elastomer standard you must meet. CSTHEATEXCHANGER reviews gasket material and compatibility as an explicit part of the custom plate heat exchanger specification.
Yoghurt viscosity depends on product type, fat content, solids, heat treatment history, temperature, and shear history. A flow rate alone is not enough to size channels responsibly. Provide viscosity data at the relevant temperatures if you have it; if you do not, tell us the product type, fat and solids content, and the upstream heat treatment so the engineering review can proceed on stated assumptions rather than silent ones.
Pressure drop is a hard constraint in a product line: the available pump head, the product's shear tolerance, and the plant layout all bound it. Our enquiry framework asks for the pressure-drop limit on each side for exactly this reason. A design that meets the temperature target while exceeding the allowable pressure drop is not a usable design.
Chilled water, glycol solution, brine, or direct refrigerant each change the design. Provide the coolant type, concentration where applicable, inlet and outlet temperatures, flow rate, design pressure and temperature, and freeze-protection requirements. For low product outlet temperatures, the approach temperature and freeze margin need explicit attention — approach temperature and freeze protection are both on our checklist.
If the line runs multiple products or variable batch sizes, state the minimum and maximum operating capacity and the allowed outlet-temperature variation. An exchanger optimised only for the nameplate point can behave poorly at low load.
Construction | Inspection and cleaning | Fit for yoghurt cooling |
|---|---|---|
Gasketed plate-and-frame (SS316 plates) | Plate pack opens; gaskets and plates individually accessible and replaceable | Suitable where regulation and practice require opening the plates for inspection, and where a viscous product needs a selectable channel geometry |
Brazed plate | Sealed unit; no mechanical opening for internal inspection | Not suited to a duty where operators must open plates for inspection |
Wide-gap / free-flow gasketed variants | Plate pack opens | Considered where the product is viscous or contains particulates; channel geometry must be confirmed against the actual product data |
Tubular heat exchanger | Different access and cleaning approach | An alternative construction where plate geometry is unsuitable; under 7 CFR 58.128 internal return tubular exchangers for milk and milk products have their own 3-A standard |
If your product contains fruit pieces, cereal, or other particulates, say so at enquiry — particulate size drives the minimum channel gap and can rule out a standard plate pattern entirely.
A selection made on water properties will under-perform on a viscous fermented product. Provide product-specific data.
SS316 plates with a gasket that is incompatible with your CIP chemistry or product pH is a short-lived installation. Specify both.
If your regulatory regime or internal standard requires the plates to be opened for inspection, the construction must allow it.
Cleaning chemistry, temperature, concentration, and cycle time influence gasket choice, surface finish, and design temperature. Send them with the process data.
Connection sizes, orientation, centre-to-centre dimensions, overall size limits, weight limit, mounting arrangement, and service clearance are all on our enquiry checklist. Supplying them early prevents site modifications later.
Both circuits should be evaluated independently, with maximum working pressure, test pressure, design temperature, and inter-circuit differential stated.
Open the plate pack for inspection at intervals frequent enough to confirm cleanliness and satisfactory condition, as required for plate-type heat exchangers in dairy service
Keep a posted cleaning regimen to ensure correct cleaning procedures between inspection periods
Verify all gaskets are tight and in good operating order; replace on a planned schedule rather than after failure
Inspect plates for cracks, pitting, and corroded surfaces — product-contact surfaces must be kept in good repair and free from cracks and corroded surfaces
Record plate positions and orientation before disassembly so the pack is reassembled correctly
Monitor pressure drop and outlet temperature trends to detect fouling or channel blockage
Confirm torque and plate-pack dimension after reassembly, against the unit's documented closing dimension
Maintain a spare-gasket and spare-plate inventory appropriate to your production risk
Work should follow the equipment documentation, your plant's sanitation programme, and the applicable regulatory requirements in your market.
Yes. CSTHEATEXCHANGER provides custom plate heat exchanger design and manufacturing, including plate material and grade, plate thickness and surface finish, gasket material and compatibility, gasketed or brazed construction, connection configuration, and design pressure per circuit — defined from your process conditions.
316 stainless steel is commonly specified for product-contact surfaces in dairy applications for its corrosion resistance. US federal dairy plant regulations require product-contact surfaces to be stainless steel or an equally corrosion-resistant material for the intended use, kept free from cracks and corroded surfaces. The final grade decision should be based on your product chemistry, temperature, CIP regime, and any standard your plant must satisfy.
A brazed unit cannot be opened for internal inspection. For plate-type heat exchangers in dairy service, operators are required to open the plates for inspection at sufficiently frequent intervals to determine whether the equipment is clean and in satisfactory condition. A gasketed plate-and-frame construction allows that.
Published dairy science describes cooling the yoghurt to around 5 °C once pH reaches approximately 4.7–4.3, to inhibit starter-culture growth and prevent further acidity increase. One-phase cooling takes the coagulum rapidly below 10 °C; two-phase cooling goes rapidly below 20 °C and then gradually to 5 °C storage, which is associated with increased viscosity and limited syneresis. Your target temperatures should follow your own product specification and food-safety plan.
Send the product type and rheology data, product inlet and outlet temperatures, flow rate or required cooling capacity in kW, product pH range, coolant type and concentration, coolant inlet and outlet temperatures, pressure-drop limits on both sides, design pressure and temperature on both sides, required plate grade and gasket requirements, CIP chemistry and temperatures, connection sizes and orientation, overall dimensional and weight limits, and any drawing, layout plan, or equipment photo.
State the applicable pressure-equipment regulations, required inspection and certification, leak-test standard, material certificates, and surface-finish requirement at enquiry. These items are part of our custom plate heat exchanger specification review, and confirming them up front keeps them inside the quoted scope.
Tell us the particulate type and maximum particle size along with the rheology data. Channel gap and plate pattern selection depend on it, and fluid cleanliness and suspended-solids content are part of our standard enquiry information.
Contact CSTHEATEXCHANGER with your process data and installation constraints. Our team supports the project from requirement review and technical communication through selection, drawing confirmation, manufacturing, inspection, and delivery.
Yoghurt cooling rewards a heat exchanger that was specified for the real product: 316 stainless steel plates for an acidic product-contact environment, a gasket chosen against your actual pH and CIP chemistry, channel geometry matched to a viscous and shear-sensitive coagulum, a plate pack that opens for the inspection your regulator and your sanitation programme expect, and design pressures evaluated independently on each circuit.
At CSTHEATEXCHANGER, we combine custom plate heat exchanger engineering, structured specification review, drawing confirmation before manufacture, and OEM/ODM support for dairy and process customers worldwide. Whether you are building a new yoghurt line, adding a second-stage cooler, or replacing an exchanger that no longer holds its outlet temperature, we can define the right unit for the duty.
Send your product data, coolant conditions, CIP regime, connection details, and layout drawings to CSTHEATEXCHANGER today. Contact our engineering team for a custom SS316 gasketed plate heat exchanger review for your yoghurt cooling application.
