Kaşar Cheese Drying & Maturation: Humidity Control Guide

Kaşar (a Turkish pasta-filata cheese similar to kashkaval) is a semi-hard yellow cheese and one of Türkiye's most technologically demanding dairy products. Its characteristic elastic texture, balanced salt-acid profile and long shelf life depend directly on tightly controlled drying and maturation processes. During this phase, precise relative-humidity management determines both product quality and compliance with the Turkish Food Codex moisture-content limits. Poor humidity control means more than yield loss, it opens the door to mould and to microbiological risks such as Listeria monocytogenes.

10:1

Milk-to-Cheese Ratio

10–14°C

Maturation Temperature

85–90%

Maturation Relative Humidity

≥ 120 days

Maturation for "Eski" (Aged) Kaşar

This in-depth technical guide approaches kaşar cheese drying and maturation humidity control from an engineering perspective. Starting with milk processing, it covers scalding (haşlama), brining, surface drying, maturation room design, condensing vs silica gel rotor dehumidifier selection, mould prevention strategies, pathogen risk management (e.g. Listeria) and a moisture-load calculation for an example 20 ton/month plant, step by step. As NKT – Nem Kontrol Teknolojileri, our aim is to provide dairy industry engineers and plant managers with actionable, measurable and sustainable reference solutions.

Kaşar cheese maturation room: industrial humidity control application — Industrial kaşar cheese maturation room, controlled humidity and temperature environment.

Key engineering concepts: surface drying, proteolysis, lipolysis, water activity (aw), relative humidity (RH), dew point (DP), psychrometric balance, air changes per hour (ACH), capillary crazing (rind tensile cracking), Listeria monocytogenes preventive hygienic design, FIFO rotation, weight-loss management.

Kaşar Production Process and Humidity-Critical Steps

Kaşar belongs to the pasta filata family of semi-hard yellow cheeses. Historically developed in the Thrace, Kars and Kayseri-Pınarbaşı regions of Türkiye, today it is manufactured at industrial scale under modern hygienic protocols. The Turkish Food Codex Cheese Communiqué (No. 2015/6) defines kaşar as a pasta-filata cheese that may be marketed fresh or ripened. The term "eski" (aged) may be used only for kaşar ripened for at least 120 days. The longer the ripening, the more important correct room-climate management becomes.

The communiqué sets no general minimum ripening time for kaşar; the product must meet its compositional criteria, and ripened cheese must state the ripening time on its label. This framework is the fundamental constraint of maturation room design.

General Production-Flow Schema

Turkish Food Codex Cheese Communiqué: kaşar cheese reference table

The full kaşar process flow makes it clear at which step humidity control becomes critical:

Raw milk is first pasteurized via HTST (72°C, 15 s) or LTLT (63°C, 30 min). After cooling to 30–32°C, the milk is inoculated with mesophilic Lactococcus lactis starter culture. The starter converts lactose to lactic acid; when pH reaches 6.3–6.4, rennet is added. The curd sets within 35–45 minutes and is then cut. The curd pieces undergo syneresis, expelling whey, while acidity continues to develop.

The step that truly separates kaşar from other cheeses is scalding (pasta filata). Once the curd's pH falls to about 5.1–5.3, the pieces are immersed in 70–75°C salted water and kneaded. During this stage casein protein fibres realign and the characteristic fibrous, elastic kaşar texture emerges. The kneaded mass is pressed into moulds and set with cold water. Depending on the plant's method, the shaped blocks are then salted in brine or by dry salting; the salting area must be kept cool. Salt supports flavour development while also building the initial surface barrier.

Industrial Tip As the salting environment warms up, salt uptake and microbial activity speed up. The salting room therefore needs its own temperature and humidity control. The exit from brining is the moment when the kaşar surface carries its highest water activity; starting the subsequent surface-drying phase with the right parameters is critical.

Drying Phase and Surface Rind Formation

Kaşar blocks leaving the brine bath are loaded onto stainless steel (AISI 304) hygienic trolleys and transferred to the drying room. In some plants this is integrated with the maturation room; in others, a dedicated drying room precedes maturation. The fundamental goal of surface drying is to rapidly reduce water activity and initiate a healthy rind.

The Engineering Significance of the Surface Rind

The rind acts as the cheese's "own packaging", a thin surface layer whose quality governs several functions:

Water-vapour barrier: Releases internal moisture at a slow, controlled rate; this balances weight loss.
Microbiological shield: As the surface dries, water activity (a_w) drops; the habitat for pathogens such as Listeria and spoilage bacteria such as Pseudomonas shrinks.
Thermal homogeneity: A dense rind buffers the internal temperature against external fluctuation.
Flavour compartment: Keeps the volatile flavour compounds (short-chain fatty acids, esters) produced during maturation contained within the interior matrix.

Target Parameters During the Drying Phase

Based on kaşar practice in the literature and typical plant recipes, the following ranges can be used as starting values for surface drying (rind formation); the exact values are set by the product recipe:

Parameter	Target Range	Tolerance Note
Temperature	12–16°C	±1°C band
Relative Humidity	80–85% RH	Avoid long periods below the band (rind-cracking risk); dew point ≈ +8.7…+13.5°C
Air Velocity (shelf level)	0.2–0.4 m/s	No high-velocity air directly on the rind
Circulation Airflow	Set by fan speed (VFD)	Chosen for shelf-level air velocity; no dead zones
Fresh Air	Minimum required	For CO₂/odour control and slight positive pressure
Duration	≈ 3–7 days	Depends on block size and recipe

Over-Drying Risk If relative humidity falls well below the drying band (80%) or shelf-level air velocity exceeds 0.5 m/s, the surface dries faster than internal moisture can migrate outward. The result is capillary crazing fractures in the rind. Crazing not only inflates weight loss but also breaches the microbiological barrier, opening the door to mould and pathogens. The risk is most pronounced in 3–5 kg block formats, where the interior-surface moisture gradient is steepest.

Maturation Physiology: Enzymatic and Microbial Processes

Maturation is the phase that gives kaşar its real technological identity. Biologically, three core mechanisms run in parallel: glycolysis, proteolysis and lipolysis. The rate of each is governed directly by ambient temperature and indirectly by water activity (a_w), and water activity itself depends on the balance between the cheese's internal moisture and external relative humidity.

Proteolysis: The Architect of Texture and Flavour

The dominant protein in cheese, casein, is degraded during maturation by several enzyme systems. Residual chymosin from rennet cleaves casein into large peptides (e.g. β-CN f1–192). Proteases from the starter and secondary cultures then progressively break these down into smaller peptides and finally into free amino acids. Proteolysis is what produces kaşar's distinctive sliceable, elastic texture that stretches when melted.

Lipolysis and the Aroma Complex

Milk triacylglycerols are partially hydrolyzed by lipoprotein lipase and microbial lipases, releasing free fatty acids. Oxidation, esterification and subsequent reactions of these acids generate the characteristic volatile aroma profile of kaşar, notably butyric acid, caproic acid and ethyl esters. Excessive humidity and temperature accelerate lipolysis uncontrollably, producing rancid off-notes.

Glycolysis and pH Trend

During maturation, part of the lactic acid produced by the starter culture can be converted to compounds such as acetate and CO₂. pH typically rises slightly from a 5.1–5.3 band to 5.3–5.5 over the first 30 days. This pH range favours mould growth, which is why keeping relative humidity below the upper limit of the maturation band (90%) and avoiding stagnant air are critical for microbiological safety.

Engineering Note When ambient temperature and relative humidity are tightly controlled, all three biochemical processes converge to deliver what we call the "kaşar character", that balance of taste and texture. This balance point is set by the product recipe, and the dehumidifier must be selected with enough capacity to hold it.

Target Humidity and Temperature Ranges

Before packaging, the kaşar climate falls into two main phases: surface drying for rind formation and maturation for inner ripening. The ranges below are typical literature values; the exact values are set by the product recipe. In industrial production kaşar is often vacuum-packed after a short surface-drying phase and kept cold in its packaging, while rinded ripening is the traditional method.

Phase	Duration	Temperature	Relative Humidity	Dew Point	Goal
Surface Drying (rind formation)	≈ 3–7 days	12–16°C	80–85%	≈ +8.7…+13.5°C	Removing surface water, rind formation
Maturation (rinded)	Per recipe; ≥ 120 days for "eski"	10–14°C	85–90%	≈ +7.6…+12.4°C	Proteolysis, lipolysis; flavour and texture development
Cold Storage (vacuum-packed)	Until consumption	≈ 4–7°C	Not decisive for packed product	—	Stable storage

A key insight from this table is that temperature alone is not enough. Two different RH values at the same temperature produce two different equilibrium water activities, and therefore very different maturation behaviour. Modern dairy plants place RH sensors not at a single point, but at at least three locations: room inlet, room outlet and mid-room shelf height.

Warning: Critical Deviation Bands If RH stays above 90% for long periods with stagnant air, moisture accumulates on the surface; this favours moulds such as Penicillium, spoilage bacteria such as Pseudomonas and Listeria monocytogenes. If RH stays below the drying band for long periods, the rind cracks, shrink increases and the product's composition may drift off target. Both extremes carry economic and regulatory consequences.

Maturation Room Design + Figure 1: Kaşar Maturation Room Cross-Section Diagram

A kaşar maturation room must be treated as an HVAC micro-climate system. The design approach holistically balances product load, cooling load, moisture load, hygienic-design criteria and energy efficiency. In this article's 20 ton/month example, each room is sized at roughly 12 m × 8 m × 4 m (LxWxH), giving a net volume of about 384 m³.

Structural Design Principles

Industrial kaşar maturation room: cheese loaves resting on stainless-steel racks in staged sequence

Sandwich panel walls/ceiling: 100–120 mm PUR/PIR polyurethane core, food-grade stainless or white-painted galvanised steel facing; thermal transmittance (U) ≤ 0.25 W/m²K.
Floor: Epoxy-coated concrete; 1–2% slope; central drain; coved wall-floor radius for hygienic cleanability.
Doors: Automatic sliding or hygienic swing-cushioned door; air-curtain mandatory; airlock with double doors standard on larger plants.
Lighting: IP65 LED panels; 200–300 lux; spectra chosen for low photo-oxidation risk.
Drainage: Independent wash-down drain lines; back-flow prevention on floor gulleys as part of hygienic design.

Air Circulation and Distribution

Kaşar maturation and resting room: industrial rack layout

Success in a maturation room is directly tied to homogeneous air distribution. The target is to hold every shelf position within ±3% RH and ±1°C of the set-point. This requires:

Slow, balanced overhead supply through textile (fabric) diffusers or perforated metal diffusers
Floor-level return (0.3–0.5 m above the floor); moist and CO₂-laden air descends
Enough clearance between racks for air to reach every product surface
VFD-driven circulation fans; airflow modulated to deliver 0.2–0.4 m/s at shelf level
Fresh air kept to the minimum required; at least F7 filtration, F9 where the risk assessment calls for it

The following cross-section diagram shows the airflow architecture of a typical 12 m × 8 m × 4 m kaşar maturation room. The diagram identifies the dehumidifier, cooling coil, cheese wheels/blocks, rack layout and the direction of supply and return airflows.

Figure 1: Kaşar Maturation Room Cross-Section Diagram, dry air is supplied from the ceiling, circulated through the racks, and humid air is drawn out near the floor; the cooling coil and dehumidifier operate together at ceiling level.

Condensing vs Silica Gel Rotor Dehumidifier Comparison (Cheese Context)

The key to technology selection is the room's dew point and temperature. In the surface-drying room the dew point is about +8.7°C at 12°C / 80% RH and about +13.5°C at 16°C / 85% RH. In the maturation room it is about +7.6°C at 10°C / 85% RH and about +12.4°C at 14°C / 90% RH. These values sit right at the boundary between the two technologies.

Room Condition	Assessment
Dew point +10°C or higher, room 15°C or warmer	Condensing units operate in their efficient zone
Dew point +5…+10°C, or room continuously below 15°C	Condensing units work, but capacity and COP drop; size from the low-temperature capacity curve and compare energy with a silica gel rotor or hybrid system
Dew point below +5°C	Silica gel rotor; in a condensing unit the evaporator ices up and defrost typically cuts capacity by 30–50%

Condensing (Mechanical / Compressor-Based) Dehumidifiers

Condensing systems use a refrigeration cycle to condense moisture on a cold evaporator surface. They are efficient at dew-point targets of +10°C and above; the practical lower limit is a dew point of about +5°C. Below that, the evaporator surface drops below 0°C and ices up. When the ambient temperature falls below 15°C, capacity and efficiency also drop markedly. The CD series operates at +10…+40°C ambient and has hot-gas defrost, while catalogue capacities are rated at 32°C / 90% RH. For a 12–14°C kaşar room, the unit must therefore be selected from its low-temperature capacity curve.

In kaşar plants, condensing units are strongest on the fresh-air line, where warm and humid outdoor air is pre-treated, and in surface-drying rooms running close to 15°C.

CD 160-980 · CONDENSING

Condensing Dehumidifier for Fresh-Air Pre-Treatment and Drying Rooms

Galvanised steel housing, copper-tube heat exchanger, ducted installation, hot-gas defrost. 160 – 980 L/24h (rated at 32°C / 90% RH); operating range +10…+40°C.

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Silica Gel Rotor (Desiccant / Adsorption) Systems

Silica gel rotor dehumidifiers hold moisture by physical adsorption. Process air is dried as it passes through the rotating silica gel rotor, while the rotor's reactivation sector is regenerated with hot air at 100–140°C. These units operate at −20…+40°C ambient, can reach low dew points, and are far less affected by low room temperature than condensing units.

In kaşar plants, a silica gel rotor is a strong option for maturation rooms that run continuously below 15°C. Because the rotor unit adds heat to the room, the room evaporator must be sized for this extra load. Hybrid systems, which combine a pre-cooling coil and a rotor in one casing, use the strengths of both technologies. NKT supplies the ADS, AD, ADP and ADE silica gel rotor series and hybrid systems of the Italian manufacturer TFT – Tecnofrigo Tuscany, for which it is the authorised distributor.

AD 270-1700 · SILICA GEL ROTOR

Silica Gel Rotor Dehumidifier for Low-Temperature Maturation Rooms

Made by TFT – Tecnofrigo Tuscany; AISI 304 stainless steel housing, electric regeneration. 270 – 1,700 m³/h airflow; silica gel rotor technology operating at −20…+40°C ambient.

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Engineering Note When a single plant runs several room types (surface drying, maturation, fresh-air pre-treatment), the technology is selected separately for each room according to its own dew point and temperature. When several units serve the same room, their start-up sequence must be defined; otherwise they work against each other, wasting energy and causing humidity swings.

Mould Control, Surface Drying and Listeria Prevention

Microbiological safety is the invisible but most critical function of HVAC design in a kaşar maturation room. Humidity, temperature and circulation directly influence three core microbiological risks: mould growth, Listeria monocytogenes contamination, and surface bacterial biofilms.

Mould Sources and Preventive Parameters

The most common mould genera in maturation rooms are Penicillium, Aspergillus, Cladosporium and Mucor. Growth requires:

Free surface water: condensation forms when the product surface is colder than the air's dew point (e.g. air at 13°C / 90% RH has a dew point of ≈ +11.4°C)
High surface water activity; since many Penicillium species grow down to a_w ≈ 0.80, RH control alone does not stop mould, it limits growth rate
Maturation-room temperatures slow mould growth but do not stop it
Stagnant air (corners with poor circulation)
Non-hygienic surfaces (wooden pallets, cracked walls, poorly cleaned racks)

The HVAC mould-prevention strategy comprises:

RH control: 85–90% band during maturation; alarms above 90% and below the drying band
Continuous air circulation: No dormant zones; fans never switched off
Surface drying: Controlled drying phase in the first days (≈ 3–7 days); removing free surface water and forming the rind
Filtration: At least F7 including fresh air, F9 where the risk assessment calls for it; minimises mould-spore ingress
UV-C sterilization (optional): Installed in the return-air duct; inactivates mould spores, but no direct line-of-sight onto product
Hygienic design: Coved wall-floor radius, stainless steel shelving, crack-free flooring

Listeria monocytogenes Risk and HVAC Approach

Listeria monocytogenes is one of the most critical pathogens in kaşar production. As a psychrotrophic organism it can multiply even at refrigeration temperatures; it generally needs a_w ≥ 0.92 to grow. Under the microbiological criteria of Regulation (EC) 2073/2005 and the Turkish Food Codex, in ready-to-eat foods that support its growth Listeria must be absent in 25 g before the food leaves the producer's control, and must not exceed 100 cfu/g during shelf life.

Listeria Prevention, the HVAC Dimension Drains, door thresholds, fan filters and air ducts are the most common Listeria "harbor sites". A maturation room must run a positive air pressure (+5 to +10 Pa relative to the adjacent corridor); all return air should be collected via a single controlled path; drain siphons must appear on the weekly cleaning checklist. An air curtain on the door minimises external pathogen ingress when the door opens.

Surface Maintenance Protocol

During the first 7 days, inspect kaşar surfaces daily; revisit airflow pattern if local moisture accumulation appears
At early mould observation, wipe the surface with food-grade brine or a permitted natural antifungal agent (e.g. natamycin within regulated surface limits)
Before vacuum packaging, perform visual inspection and hardness test
Batch-level temperature-humidity records retained for the period set in the plant's HACCP procedure

Case Study: 20 Ton/Month Kaşar Maturation Plant (Worked Example)

The following example shows how the moisture load is calculated; every plant should replace the assumptions with its own data. Target output is 20 tons of kaşar per month, block weight 2 kg and, per the producer's recipe, a maturation time of 90 days. Surface drying takes place in a separate room; the calculation covers the maturation rooms.

System Parameters

Parameter	Value	Notes
Monthly Output	20,000 kg	10,000 × 2 kg blocks/month
Maturation Period	90 days	Producer recipe (the communiqué sets no general minimum for kaşar)
Stock in Maturation	≈ 60,000 kg	3 months × 20 ton
Number of Rooms	3 parallel rooms	Sequential loading for FIFO
Room Volume (each)	384 m³	12 m × 8 m × 4 m
Design Point	12°C / 85% RH	Dew point ≈ +9.6°C; 7.4 g/kg (lower edge of the maturation band)
Product Density	≈ 52 kg/m³	20,000 kg / 384 m³ (per room)
Fresh Air (per room)	192 m³/h	0.5 air changes per hour (assumption)
Outdoor Design Condition	30°C / 70% RH	18.8 g/kg (assumption)

Moisture Load Calculation

The total moisture load has four components:

W_total = W_product + W_freshair + W_infiltration + W_personnel

Product evaporation (W_product): Assuming an average daily weight loss of 0.1% (to be verified against the recipe), 20,000 kg × 0.001 = 20 kg/day.
Fresh air load (W_freshair): 192 m³/h × 1.2 kg/m³ × (18.8 − 7.4) g/kg ≈ 2.6 kg/h. This load is removed in the central unit on the fresh-air line, before the air enters the room.
Infiltration (W_infiltration): Door openings and structural infiltration ≈ 2 kg/day (assumption).
Personnel: 2 persons × 4 hours × 100 g/hour = 0.8 kg/day.

Because the fresh air is treated centrally, each maturation room's unit only handles the product, infiltration and personnel load: 20 + 2 + 0.8 = 22.8 kg/day, or ≈ 28.5 kg/day (≈ 1.2 kg/h) with a 25% safety margin. The central fresh-air unit's load for three rooms is 3 × 2.6 ≈ 7.9 kg/h, or ≈ 9.8 kg/h with the 25% margin. Assigning the same fresh-air load to both the central unit and the room units would count it twice and lead to oversized equipment.

Recommended Configuration

Central fresh-air pre-treatment: With an outdoor dew point of about +24°C, a condensing unit works efficiently here; the air is dried down to the room dew point (≈ +9.6°C) before distribution. A ducted CD 160-980 model is selected from its capacity curve at the inlet condition.
Room units: The room is at 12°C, i.e. continuously below 15°C, and its +9.6°C dew point lies in the +5…+10°C intermediate zone. For a load of ≈ 1.2 kg/h per room, a silica gel rotor (ADS / AD series) or hybrid unit and a condensing unit with a verified low-temperature capacity are compared on energy use before selection.
Cooling: A rotor unit adds heat to the room; the room evaporator is sized for this extra heat load.
Measurement and control: Relative humidity and temperature are measured at three or more points per room; where possible, humidity is controlled on dew point.
Humidification: When the product load falls, the cooling coil can over-dry the room and push RH below the band; hygienic steam humidification may then be needed.

Annual energy consumption must be calculated separately from the selected units, local climate data and operating hours. In this example a large share of the dehumidification energy comes from fresh air in summer, so keeping fresh air to what is actually needed is the most effective saving.

Energy Efficiency and Periodic Maintenance

Energy Optimization

A significant portion of operating costs in kaşar maturation plants comes from refrigeration and dehumidification. The main energy-saving approaches are:

Heat recovery: Plate-frame heat exchanger on the fresh-air intake; recovers heat/cool from the exhaust return air (seasonal effect)
VFD-driven fans: Variable-speed instead of fixed-speed; significant savings at part load
Night set-point shift: Loosen RH set-point by ±1% during unattended hours
Cold storage of vacuum-packed product: Packed cheese exchanges no moisture; the dehumidifier can run at a lower stage
Keeping fresh air to what is needed: In summer most of the moisture load comes from fresh air

Periodic Maintenance Schedule

Component	Monthly	Quarterly	Semi-Annual	Annual
Air filters (G4, F7, F9)	Visual check	Clean / replace	Full replacement	Class review
Evaporator coil	Surface check	Cleaning	Detailed wash	Leak test
Condensate drainage	Flow check	Siphon cleaning	Line check	Drain piping inspection
Silica gel rotor	—	Visual	Performance test	Wash / seal check
RH / Temperature sensors	Data check	Drift check	Calibration	Certified calibration
Fan motors	—	Lubrication / check	Vibration test	Bearing replacement (if needed)
HACCP documentation	Data archival	Internal audit	External audit	System update

Sustainability Note Regular maintenance and correct filtration preserve unit performance. With proper filtration a silica gel rotor typically lasts about 10 years, and with regular maintenance the unit can run for many years. NKT provides technical service and spare-parts support for the units it supplies.

NKT and TFT – Tecnofrigo Tuscany

NKT – Nem Kontrol Teknolojileri is a supplier of industrial dehumidifiers. For dairy and cheese plants it provides capacity-calculation support for selecting the right unit, technical service and spare parts. Project design, installation and plant automation are outside NKT's scope; they are carried out by the plant's mechanical and automation contractors.

Unit selection and capacity-calculation support: Choice of technology and model based on room condition, dew point and moisture load
Equipment supply: Condensing (CD 160-980, CD 1200-3000, CDW 16 / CDK 44-100), silica gel rotor (ADS, AD, ADP, ADE) and hybrid units
Technical service and spare parts: Maintenance and parts support for supplied units

TFT – Tecnofrigo Tuscany (Italy)

NKT is the authorised distributor in Türkiye for the Italian manufacturer TFT – Tecnofrigo Tuscany. TFT silica gel rotors are supplied in stainless or galvanised steel cassettes with 200 mm and 400 mm depth options and are used in low-temperature maturation and freezer-room applications.

Conclusion and Practical Recommendation Kaşar quality is shaped by the balance of the air in the surface-drying and maturation rooms. Holding a recipe-specific set-point within 12–16°C / 80–85% RH for surface drying and 10–14°C / 85–90% RH for maturation, inside a narrow band, delivers the right texture, controlled weight loss and microbiological safety. Because these rooms have dew points of roughly +7.6…+13.5°C, the technology is chosen by room temperature: in rooms below 15°C, condensing, silica gel rotor and hybrid options should be compared on energy use.

For help selecting the right dehumidifier for your drying and maturation rooms, contact NKT.