Chocolate business

Tempering Machines: Batch vs Continuous, How to Choose

By Oliver BennettPublished October 15, 2026Updated October 15, 202613 min read

A tempering machine brings melted chocolate into temper, either by cooling and rewarming it under stirring or by adding crystals that are already stable, and then holds it there while you mold, dip or enrob. Which one you need depends on how much chocolate you use in a day, how often you switch between chocolates, and how you’ll check the result. Why tempering matters, down to the cocoa butter crystals, is in what is chocolate tempering.

What a tempering machine has to do

A tempering machine has to grow enough stable crystals and spread them evenly through the chocolate, then hold it at that point without letting it crystallize further. A patent for a tempermeter describes what goes wrong on each side: too few crystals mean very long setting times in the final cooling, poor gloss and a shorter shelf life, while too many raise the chocolate’s viscosity, so it contracts less as it cools and again ends up dull and short-lived.

The crystals come from one of two routes. The classic one is a temperature cycle: melt completely, cool under stirring until crystals form, then rewarm to just below the point where the stable crystals melt. The temperatures, from a 2025 review, are in the tempering section of the production line guide. The other route is seeding, where stable crystals go in ready-made.

The four kinds of machine

Tempering machines fall into four groups: tabletop bowls, wheel machines, screw-pump tank machines and industrial columns, and they differ most in where the crystals come from. In their makers’ own descriptions, bowl and wheel machines depend on seed chocolate added by the operator, while screw-tank and column machines cool and rewarm the chocolate themselves.

Every machine detail below is a maker’s own claim, taken from maker pages on October 12, 2026, and no single maker’s figure is the norm for its class.

Tabletop bowl machines (batch, seeded)

A bowl machine melts and tempers one batch at a time in a turning bowl, and the one bowl maker that spells out its method asks the operator to seed. According to that maker’s FAQ, the machine beeps twice at 108 °F to prompt you to add seed chocolate. The same FAQ warns that the turning bowl keeps crystals growing until the chocolate gets too thick to work; the fix is to raise it to 94 °F and bring it back down to the temper point.

That maker’s mid-size model takes 3 to 10 pounds per batch, is rated for up to 100 pounds a day and, by the maker’s account, holds temper for over 15 hours, heating with forced hot air. A second maker’s small bowl machine has a 3 kg tank and is air-cooled, and its page doesn’t say how it tempers.

Bowl machines suit a chocolatier who dips, fills a few molds and switches between dark, milk and white through the day. Their weak point is that the temper depends on the person running them: seeding at the right moment, and catching the chocolate before it thickens.

Wheel machines (heated tank and wheel, seeded by hand)

A wheel machine is a heated tank with a turning wheel that lifts the chocolate and carries it out for molding, and its makers describe tempering by seeding. One maker’s small wheel machine is pitched at schools, bakeries and small workshops; at that volume, the maker says, the wheel alone keeps the chocolate mixed. For larger volumes it adds a stirring device at the bottom of the tank.

A second maker’s wheel machine has a 14 kg tank and tempers melted chocolate by adding callets. Its 30 kg sibling adds a vibrating table and a stirring mechanism in the vat. Neither maker gives a figure in kg per hour.

Wheel machines suit hand molding and dipping in quantities a bowl can’t hold. Neither maker describes the machine making crystals on its own: it melts, holds and moves the chocolate, and the temper comes from the seed the operator adds. Consistency rests on the operator, as it does with a bowl.

Screw-pump tank machines (small continuous)

A screw-tank machine keeps melted chocolate in a heated tank and pumps it up with a screw, tempering it continuously for as long as you draw from it. One maker describes a steel screw pump that comes out in a few steps for cleaning with water, and says its machines can keep tempering without stopping for up to 12 hours in a working day.

Here the machine sets the cycle. A second maker lists its screw system as fully automatic at 45, 27 and 30 °C, the melt, cool and rewarm steps of the classic cycle. At the upper end of this size range, some machines use a small tempering column instead of a screw, and one compact continuous machine adds a built-in decrystallization stage.

These machines suit daily molding in one or two chocolates, or a small enrober running for part of the day. Their weak points are the capacity figure, which says little without its conditions, and the water cleaning some makers describe, which can sit badly with a dry chocolate plant.

Continuous column tempering machines (industrial)

An industrial column pumps chocolate through a stack of chambers that alternate with chambers carrying a heating or cooling medium, so the chocolate is cooled and rewarmed as it flows. That layout is described in a patent for a continuous tempering apparatus.

Makers differ in how they control the flow inside. One column maker claims a first-in, first-out flow with a constant dwell time, scrapers to spread the crystals, and a steady degree of temper even when the infeed temperature or throughput varies. A second gives each zone its own water heating and cooling. A third separates cooling from shearing, reaches exit temperatures as low as 27 °C, and lets the operator set exit temperature and temper index independently. A 1998 study, summarized in the production line guide, found that a high-shear crystallizer matched a conventional continuous machine at a lower outlet temperature.

Columns are built for molding and enrobing lines that run for hours. One maker says its smaller in-line machine, with a 35 kg buffer tank, mainly feeds enrobers, small depositors and decorating systems. Their weak points are size and utilities: they need cooling water or refrigeration sized to the flow, and one machine running several recipes needs zones you can set per recipe.

Seeding with cocoa butter crystals

Seeding adds ready-made stable crystals to chocolate instead of growing them in the machine. A 2021 study by Böhme and colleagues calls seeding with cocoa butter crystals “an established alternative” to traditional stir and shear tempering. They seeded a nougat with cocoa butter crystals at 0.5, 1 and 2%, and the measured temper degree rose with the dose, from 5.1 to 5.8 to 6.6.

The industrial version doses a crystal suspension into the flow. A 1999 patent by Windhab and Zeng describes dosing it continuously at a crystal share of 0.01 to 0.2% by weight into the mass, precooled to between 32 and 34.5 °C in the case of pure cocoa butter fat. The patent claims that conventional precrystallizers, with exit temperatures around 29 to 31 °C, react sharply to the usual production deviations of 0.5 to 1 °C, while comparable swings with seed crystals, up to around 34 °C, show no influence on precrystallization quality. That is a patent claim, not a peer-reviewed measurement.

Cocoa butter crystal powder is sold as an ingredient for the same job. One ingredient maker’s instructions call for 1%, or 10 g for 1 kg of chocolate, added when the chocolate is at the right temperature. Seeding with chopped tempered chocolate, the bench version, is in how to temper chocolate at home.

Batch or continuous: reading the capacity figure

A tank size is how much chocolate the machine holds, kg per hour is how much tempered chocolate it delivers, and neither tells you the other. Makers call both “capacity”, and the bowl maker above uses a third unit, pounds per day.

Two 12 kg screw tanks from different makers are listed at 45 and 55 kg per hour. A third maker lists a 60 kg tank machine at 150 or 250 kg per hour, while another of its models, with 60 or 80 kg tanks, does 45 to 100. The flow comes from the cooling and the column, so the tank says little about it. One more kind of figure to watch for: one maker says its 24 kg model tempers a full tank in 15 minutes, which is the start-up time, a different number from the hourly flow.

Only one maker in that set says what its figure depends on. Its column is rated at up to 6,000 kg per hour for chocolate, 4,500 for cocoa liquor and 2,500 for cocoa butter, calculated for a maximum viscosity of 50,000 cP at 40 °C (untempered, at a shear rate of 5 s⁻¹), cooling water up to 12 °C and particles up to 40 μm.

A rated figure is also a ceiling. Another column maker gives the working range of its flexible model as roughly 30 to 100% of the nominal output, which matters if your line runs well below the machine’s top speed.

To compare two vendors, each figure has to state the product and recipe, the format, how time is counted and which machine is the bottleneck. Those four things a capacity claim must state are set out in the production line guide. What happens to the tempered chocolate next, in solid, shell and one-shot molds, is in chocolate molding.

How you’ll know it’s in temper

In a small workshop, a strip test tells you whether the chocolate is in temper; on a production line, a tempermeter or an inline meter puts a number on it. The strip test, a smear left to set at room temperature and checked for gloss and snap, is described in how to test temper, with the glossary entry under temper test.

A tempermeter cools a small sample and records its temperature as it sets. The tempermeter patent describes a sensor near the center of the sample and a unit that plots temperature over time; from that temper curve, a skilled reader judges the tempering level and temper index.

Instruments add their own readouts. One maker’s brochure says its meter shows the curve with tangents at two inflection points, plus a temper index, a slope and a unit of its own. On a line, another maker’s inline meter sits in the piping of the tempering machine or the enrober, measures every 6 minutes depending on the chocolate, and raises an alarm when the curve deviates.

There is no single correct temper index. A 2020 study by Barišić and colleagues gave its desired range as 4 to 7, measured on one maker’s instrument. The Böhme seeding study, on an instrument from the same maker, read 5.1 to 6.6 depending on the seed dose.

A 2019 study by Homayouni Rad and colleagues used a different maker’s pilot instrument with a target of 4.5 to 5.5. Three studies, two instrument families, three different targets.

So don’t compare machines on a promised temper index. Ask which device measures the output, which target range the vendor works to for your chocolate, how often it’s measured, and what the machine or the operator does when the reading drifts.

Cleaning, changeovers and utilities

At a changeover, whatever chocolate sits in the tank, pump and pipes has to come out or be pushed through by the next one, and the less a machine holds, the less there is to clear. One column maker names its low mass content as an advantage when changing chocolates. Another claims its column holds much less than “traditional” machines without defining them. A third takes the opposite route and offers a 200 kg buffer tank so pigmented, flavored or dedicated chocolates get their own.

Cleaning methods split by size. One column maker sells a rinsing trolley with filters and a pump that cleans with little rinsing mass, for machines up to 3,600 kg per hour, with one trolley serving several machines. Another column lists cleaning in place. Among smaller machines, one has a column that retracts for cleaning and another a screw that comes out to be washed with water between chocolates. Water in a dry plant is a food safety question; questions 4 and 16 of the chocolate equipment RFQ checklist cover dry cleaning and allergen changeovers.

Cooling is the utility that separates the classes. One maker’s compact continuous machine has its own refrigeration unit and needs only one power connection, and one screw-tank maker lists a built-in cooling unit on each model. The industrial column rated by product type is calculated for cooling water up to 12 °C, and its maker asks that the water’s temperature not move more than 0.5 °C, nor its flow more than 2.5%, over 10 minutes.

Power runs from 750 W at 110 V for a mid-size bowl machine and 0.7 kW single-phase for a 12 kg screw tank to 3 x 400 V for an industrial column.

Which machine for which workshop

Match the machine to how long you run one chocolate and how many you switch between in a day.

A workshop that switches chocolates more often than it fills molds is better served by small batches. Once one chocolate runs most of the day, a machine that tempers continuously takes the crystal control off the operator, which is where batch machines are weakest. A plant running only compound coating can skip all of this, as real vs compound chocolate explains.

Questions to ask a tempering machine vendor

Put these to every vendor in writing, alongside the general list in the RFQ checklist.

• At what flow, for which chocolate? Ask for kg per hour with the chocolate, its viscosity, the infeed and exit temperatures and the cooling water temperature stated.
• How long to temper a full tank, and how long does it hold? For batch and tank machines, ask for the two separately.
• Where do the crystals come from? Does the machine cool and rewarm on its own or expect you to seed, and what do you do when the chocolate thickens?
• How is temper measured? Ask which device, which target range for your chocolate, how often, and what happens when the reading drifts.
• How much chocolate stays inside? Ask how many kilograms remain in the tank, pump and pipes, and how they come out at a changeover.
• How is it cleaned? Dry, with a rinsing mass, or with water, and which parts come out.
• What does it need from the building? Built-in refrigeration or cooling water, at what temperature and stability; power phase and kW.
• Can we run a trial with our own chocolate? Flow, temper reading and changeover all depend on the recipe, and one maker’s own capacity figures change with the product.

Whether to build a plant at all, and at what size, is covered in how to start a chocolate factory. Every machine in the line, in order, is in chocolate production line: machines you need.

Sources and open questions

The 1998 high-shear comparison by Bolliger and colleagues was read as an abstract only.

The classic tempering cycle linked above comes from the 2025 review by Stobbs and colleagues, cited in the production line guide.

Still open:

• whether the temper index scale is the same from one instrument maker to another;
• an independent comparison of bowl, screw-tank and column machines on the same chocolate, for gloss, bloom and temper reading, which we couldn’t find;
• how much chocolate each class leaves inside at a changeover, and how long a full clean takes; no maker states either.