Water Baths
A laboratory water bath is a temperature-controlled vessel that heats samples indirectly by immersing vessels in water (or oil) held at a set temperature, rather than applying direct heat from a hotplate or oven. The surrounding liquid buffers against sudden temperature swings, giving gentler, more uniform and more reproducible warming — which is why water baths are standard equipment for incubation, enzyme and tissue culture work, sample thawing, and heating protocols across bacteriological, clinical and industrial testing laboratories.
Ecotao supplies a full range of laboratory water baths for the South African market, from a compact 5L round bath through to 58L digital circulating models, all built around grade 304 stainless steel tanks. Ranges include still, thermostatically or PID-controlled heating baths; digital internal-circulating baths with ±0.05°C stability; and a motorised metabolic shaking water bath for fermentation and dissolution work. All units are compatible with the standard Model 103 circulator and optional accessories where applicable.
How to Choose the Right Water Bath
Choosing between water bath types comes down to four practical questions: how much control you need over temperature stability, how large a sample load you're running, whether the medium will be water or oil, and whether the sample needs to stay in motion. The comparison below breaks down every model in this range against those criteria.
Temperature accuracy
General incubation, heating and thawing tolerate the wider swings typical of thermostatic and economy-range baths. Enzyme kinetics, tissue culture and fermentation work need a PID-controlled bath with a PT100 sensor and stability of ±0.5°C or tighter — the internal-circulating E-WBIC-D series (±0.05°C) is built for this tier.
Capacity & sample load
Size to the vessels you actually run, with headroom. A 5-14L bath suits small-batch tube or flask work; 20-27L covers most routine bacteriological and clinical loads; 34-58L suits multiple large flasks or shared-use benches. Baths run near their fill line lose uniformity faster when lids are opened repeatedly.
Water or oil medium
Standard water baths top out around 100°C. For protocols above that, a bath rated for oil — such as the E-WBO5-D (up to 180°C) or the 25L Economy/Digital range (up to 199°C) — extends the usable temperature range, at a wider accuracy tolerance than the same unit gives on water.
Static, circulating or shaking
Still baths are the default for simple heating. Internal-circulating models (E-WBIC-D series) actively move water through the tank to eliminate hot and cold spots. The metabolic shaking bath adds mechanical agitation for aerobic fermentation and dissolution testing where the sample must stay mixed.
Water Bath Comparison
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| Model | Capacity | Heating Range | Accuracy | Circulation | Ideal For |
|---|---|---|---|---|---|
| 40L Metabolic Shaking | 40L | Ambient +7°C to 100°C | ±0.5°C | Internal pump + mechanical shaking (38mm stroke) | Fermentation, dissolution testing, corrosion testing |
| E-WB44IC-D | 44L | RT+10°C to 100°C | ±0.05°C | Internal circulation, 22 L/min | Enzyme studies, tissue culture, high-precision incubation |
| E-WB58IC-D | 58L | RT+10°C to 100°C | ±0.05°C | Internal circulation, 22 L/min | Larger batches needing high-precision incubation |
| E-WBT20IC-D | 20L | RT+10°C to 100°C | ±0.05°C | Internal circulation, 22 L/min | Precision work needing visual sample monitoring |
| E-WBO5-D | 5L | RT+5°C to 180°C | ±1°C water / ±3°C oil | Unstirred | Compact bench use, water or oil, above-100°C protocols |
| E-WB27-D | 27L | RT+5°C to 80°C | ±0.3°C at 37°C | Unstirred | Routine incubation with a sealed gabled lid |
| 25L Economy Heatable | 25L | Ambient +10°C to 199°C | Thermostatic (standard) | Unstirred | General heating where lower accuracy is acceptable |
| 25L Digital Heatable | 25L | Ambient +10°C to 199°C | PID + PT100 (high) | Unstirred | General heating requiring digital set-point accuracy |
| 14L Water Bath | 14L | Standard heating range | Circulator-dependent | Optional Model 103 circulator | Small-batch general laboratory heating |
| 34L Water Bath | 34L | Standard heating range | Circulator-dependent | Optional Model 103 circulator | Mid-batch general laboratory heating |
| 40L Water Bath | 40L | Standard heating range | Circulator-dependent | Optional Model 103 circulator | Larger-batch general laboratory heating |
Water Bath Range
Digital Internal-Circulating Baths — E-WBIC-D Series
Actively circulated for uniform, high-precision temperature control (±0.05°C), with PID + PT100 sensing, float water-level protection and overheat cutout. Suitable for flammable liquids.
E-WB44IC-D 44 Litre Water Bath
- RT+10°C to 100°C, ±0.05°C stability
- 22 L/min internal circulation pump
- 530 × 650 × 450mm, 23.5kg
Digital internal circulating water bath with single-point calibration, PID control via PT100, and a float water-level sensor with overheat cutout for low-water protection.
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E-WB58IC-D 58 Litre Water Bath
- RT+10°C to 100°C, ±0.05°C stability
- 22 L/min internal circulation pump
- 530 × 650 × 450mm, 24.5kg
The larger-capacity model in the E-WBIC-D series, sharing the same digital PID control, float-sensor protection and flammable-liquid rating as the 44L unit.
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E-WBT20IC-D 20 Litre Transparent Water Bath
- RT+10°C to 100°C, ±0.05°C stability
- Polycarbonate transparent tank
- 350 × 525 × 360mm, 15kg
Same digital internal-circulating control as the rest of the IC-D series, with a transparent tank for visual monitoring of samples in progress.
Check StockSpecialty Baths
Shaking, compact and sealed-lid baths for specific protocols — aerobic fermentation, oil-based heating above 100°C, and sealed high-accuracy incubation.
40L Metabolic Shaking Water Bath
- Ambient +7°C to 100°C, ±0.5°C variation
- Removable shaking carriage, 38mm stroke
- 1600W, 100 × 55 × 45cm, 45kg
PID-controlled with a PT100 sensor, microprocessor speed control with digital RPM readout, and a 120-minute timer with infinity override. Suited to flasks from 50ml to 1000ml for corrosion testing, biochemical research, fermentation and thawing of blood samples.
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E-WBO5-D 5L Oil or Water Bath
- RT+5°C to 180°C, water or oil
- ±1°C water / ±3°C oil accuracy
- Internal ø240×160mm, 4kg
Compact round bath with a PTFE-coated seamless SS304 tank, external heating element, boil-dry protection and overheat cutout at 220°C. No drain valve or lid available.
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E-WB27-D 27L Water Bath
- RT+5°C to 80°C, ±0.3°C at 37°C
- Stainless steel gabled lid + element cover
- Internal 500 × 300 × 200mm, 5kg
Rapid heating with stable temperature hold once at set point, a quick-release drain valve, and a corrosion-free SS304 lid over the internal element for daily bacteriological and clinical use.
Check StockStandard & Economy Heating Baths
General-purpose heating baths built on an epoxy-coated mild steel body with a grade 304 stainless steel inner tank, compatible with the Model 103 circulator and optional gabled lids or height reducers.
25L Economy Heatable Waterbath
- Ambient +10°C to 199°C, 2000W
- Hydraulic thermostat control
- 100 × 50 × 35cm, 16kg
Water or oil bath with incoloy heating elements, a perforated diffuser for even heat distribution, an auxiliary element for rapid heat-up, and mineral wool insulation. Optional SS304 lid.
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25L Digital Heatable Waterbath
- Ambient +10°C to 199°C, 2000W
- PID electronic control + PT100 sensor
- 100 × 45 × 35cm, 16kg
Same construction as the Economy model, upgraded with electronic PID control and a digital display of set and process temperature for applications needing higher accuracy.
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14L Water Bath
- 14L capacity
- Epoxy-coated mild steel body
- 45 × 35 × 35cm, 8kg
General laboratory heating bath with a grade 304 stainless steel inner tank, compatible with Model 103 circulators. Optional SS304 gabled lids and height reducers.
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34L Water Bath
- 34L capacity
- Epoxy-coated mild steel body
- 75 × 45 × 35cm, 16kg
Mid-capacity general laboratory heating bath in the same family as the 14L and 40L models, with a grade 304 stainless steel inner tank and Model 103 circulator compatibility.
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40L Water Bath
- 40L capacity
- Epoxy-coated mild steel body
- 95 × 45 × 35cm, 17kg
The largest of the standard heating range, sharing the same corrosion-resistant construction and circulator compatibility as the 14L and 34L models.
Check StockWhere Water Baths Are Used
Incubation & bacteriological testing
Holding samples at a stable body-temperature or process-specific set point is central to bacteriological culture work and clinical testing. A still or lightly-circulated bath at general accuracy is usually sufficient here, provided the temperature stays within the tolerance a given protocol requires.
Enzyme & tissue culture studies
Enzyme reaction rates and tissue viability are highly temperature-sensitive, so this work calls for the tighter PID + PT100 control and internal circulation found in the E-WBIC-D series, where ±0.05°C stability removes the risk of localised hot spots skewing results.
Fermentation & dissolution testing
Aerobic fermentation and dissolution protocols need the sample kept in continuous motion, not just heated. The metabolic shaking water bath's motorised carriage handles this, while its internal circulation pump keeps the surrounding water at uniform temperature during the run.
Sample thawing
Controlled, gradual thawing of frozen blood or biological samples avoids the localised heat damage that a direct heat source can cause. A PID-controlled bath holding a precise, gentle temperature is the standard approach for this step.
Materials & corrosion testing
Extended immersion testing of materials at a controlled temperature relies on stable long-run performance rather than extreme precision, making the metabolic shaking bath's PID control and stainless steel tank well suited to multi-day corrosion and degradation testing.
Above-100°C oil-based heating
Where a protocol needs temperatures above water's boiling point, an oil-rated bath such as the E-WBO5-D or the 25L Economy/Digital range extends the usable range up to 180-199°C, using the same PID or thermostatic control principles as their water-only counterparts.
Frequently Asked Questions
What is the difference between a standard water bath and a digital circulating water bath?
A standard heating water bath, such as Ecotao's 14L, 34L, 40L and 25L Economy/Digital ranges, uses a still, unstirred tank with thermostatic or PID temperature control, suited to general incubation and heating where mild temperature variation across the bath is acceptable. A digital internal-circulating water bath, such as the E-WBIC-D series, adds an internal pump that continuously moves water through the tank at 22 L/min, holding temperature to within ±0.05°C and removing hot or cold spots — important for enzyme kinetics, viscosity testing and other work where uniform temperature matters more than raw heating capacity.
How do I choose the right size water bath for a laboratory?
Match bath capacity to sample load and vessel size rather than just the number of samples run at once. A 5L or 14L bath suits small-batch tube or flask incubation, 20-27L covers most routine bacteriological and clinical work, and 34-58L baths suit multiple large flasks, extended incubation series, or shared-use benches. Leave headroom in the tank — a bath run near its maximum fill line loses temperature uniformity faster when lids are opened repeatedly.
Can an Ecotao water bath be used with oil instead of water?
Yes. Models built around a stainless steel or PTFE-coated tank with an external or immersion heating element, such as the E-WBO5-D and the 25L Economy/Digital range, are rated for both water and low-viscosity oil, extending the usable temperature range up to 180-199°C. Oil accuracy is typically a wider tolerance than water accuracy on the same unit — for example ±3°C oil versus ±1°C water on the E-WBO5-D.
What temperature accuracy is needed for enzyme and tissue culture work?
Enzyme kinetics, tissue culture and fermentation studies are sensitive to small temperature drift, so a PID-controlled bath with a PT100 sensor and stability of ±0.5°C or tighter is recommended. The internal-circulating E-WBIC-D series (±0.05°C) and the metabolic shaking bath (±0.5°C) are built for this level of control. General incubation, thawing and heating tasks tolerate the wider tolerances typical of thermostatic and economy-range baths.
Is a shaking water bath different from a standard water bath?
Yes. The 40L Metabolic Shaking Water Bath adds a motorised, removable shaking carriage with a 38mm stroke and microprocessor speed control, keeping flask contents in continuous motion. This is required for aerobic fermentation, dissolution testing and other protocols where the sample must stay mixed and aerated during incubation. A standard water bath only heats — it has no mechanical agitation.
Do Ecotao water baths have stainless steel tanks?
Every model in this range uses a grade 304 stainless steel tank, with the E-WBO5-D adding a PTFE coating for extra chemical resistance. External bodies vary by model: epoxy-coated mild steel on the 14L/34L/40L standard range, ABS plastic on the compact E-WBO5-D, and powder-coated steel on the digital IC-D series.
Does altitude affect water bath performance in South Africa?
Yes, for protocols that run at or near 100°C. Water's boiling point drops roughly 1°C for every 300m of elevation, so on the Highveld — Johannesburg and Pretoria sit at around 1,700-1,750m — water boils at approximately 95-96°C rather than the sea-level 100°C. Coastal labs in Cape Town or Durban run much closer to true 100°C. For temperature-critical work at altitude, a PID-controlled bath with a PT100 sensor set to the actual required temperature, rather than relying on a visible boil, gives more reliable, location-independent results.
Need Help Choosing a Water Bath?
Ecotao's team can help you match capacity, accuracy and medium to your protocol, and confirm current stock and lead times across the full water bath range.
Head Office: +27 21 911 5835 • Zak: 086 142 8716 • Zaid: 082 390 3989 • sales@ecotao.co.za