Conching Demystified: What 24 Extra Hours Actually Does to Your Chocolate

Conching is the stage most new bean-to-bar makers under-invest in. The particle size is already small. The texture already looks smooth. The chocolate tastes reasonable. Surely it's done? It almost never is. The most common defect in first-year craft chocolate isn't bad roasting or bad tempering — it's chocolate that was pulled out of the melanger twenty-four hours before it should have been. This post is the working guide to conching: what it does, how long to do it, and how to tell when the bar is actually ready.

What conching actually does

Conching is extended mechanical agitation of liquid chocolate after particle reduction is complete. The name comes from Rodolphe Lindt's 1879 invention — the first conche was shaped like a conch shell — and the process has been refined industrially for 145 years without fundamentally changing what it does. Three things happen simultaneously:

1. Acid removal.Volatile acids (primarily acetic acid left over from fermentation) escape from the open surface of the chocolate as it's agitated. Under-conched chocolate carries residual acetic sharpness; well-conched chocolate has had time for those acids to vent.
2. Mouthfeel development. Continued shearing and agitation coats every particle more completely in cocoa butter, which is what produces the silky mouthfeel associated with good chocolate. This is why conched chocolate feels different from a paste of the same particle size.
3. Flavor integration.Aroma compounds interact, volatile harshness dissipates, and previously isolated flavor notes blend into a rounded, integrated whole. This is the least visible change and the most important — it's the difference between chocolate that tastes like ingredients and chocolate that tastes like chocolate.

Melanger conching vs. dedicated conches

For small bean-to-bar makers, grinding and conching typically happen in the same piece of equipment — a stone melanger. The stone wheels continue turning after particle size has stabilized, and that extended agitation serves as conching. For larger and industrial makers, conching happens in a separate dedicated conche capable of higher temperatures, more aggressive agitation, and better airflow for volatile removal.

The reality of small-scale craft chocolate is that your melanger is also your conche, and extending the run to 36–72 hours is how you conche. This is not a compromise — it produces genuinely excellent chocolate — but it does mean your melanger cycle time is your primary conching variable.

The 24 / 48 / 72 hour flavor curve

The single most useful thing a new maker can do is taste their own chocolate every twelve hours during a melanger run. The progression is consistent across most recipes and origins:

For most craft recipes on a small melanger, the sweet spot sits somewhere between 36 and 72 hours, clustered around 48. Delicate origins (Madagascar, Marañón) often peak at the lower end — 36–48 hours — because additional time flattens their fragile top-notes. Robust origins (Vietnam, Dominican blends) often benefit from 60–72 hour runs because the deeper Maillard character takes longer to integrate fully.

The variables that matter

Temperature

Stone melangers typically run at 40–45°C through friction alone; dedicated conches can hold 50–70°C. Higher temperatures accelerate acid volatilization but can also degrade delicate aromatics. Most small-maker stone-melanger setups don't control temperature actively — which is fine, because the natural 40–45°C range is a reasonable compromise for craft work.

Airflow

Volatile acids leave chocolate through the open surface. Stone melangers have a modest open surface; dedicated conches often have specific ventilation designs to accelerate removal. If your melanger has a lid, running with it off (or cracked) during the conching phase of the cycle measurably increases acid loss. Watch for condensation on the lid — that's literally your acid escaping.

Cocoa butter additions

Many recipes add 2–5% extra cocoa butter during the conching phase. This does two things: it improves mouthfeel (by increasing the fat fraction coating particles) and it slightly thins the chocolate for more effective agitation. The common craft move is to add butter in the last 12–24 hours rather than at the start.

Lecithin

Sunflower lecithin (or soy, for makers not allergen-conscious) at 0.3–0.5% acts as an emulsifier that helps cocoa butter coat particles more uniformly. It doesn't replace conching, but it lets you achieve similar mouthfeel with less total conche time. Many pure craft makers skip lecithin entirely; others add it at hour 24 or later.

Starting particle size

Conching is more effective when particle size is already below about 25 microns. Finishing particle reduction first, then conching, is the model dedicated conches use. In a melanger, these phases overlap — which is why combined grind/conche times tend to run longer than a purpose-built conching stage would.

The under-conche trap

New makers run short first-batch cycles because they don't have to wait — the melanger will happily stop when they tell it to, and 24 hours is already more than they expected. The finished chocolate is smooth. It tempers. It tastes like chocolate. Everything is fine. Except the bar has a sharp acid top-note, a short finish, and a slightly angular mid-palate — all symptoms of under-conching that the maker doesn't yet have the vocabulary to name.

The fix is experimental: run the same recipe for 36, 48, and 72 hours across three batches, and taste them blind side-by-side. The difference is almost always surprising. Makers who do this exercise once rarely need to do it again — they've internalized what 24 additional hours of conching feels like on the palate.

Production implications

Conching time is a throughput constraint. An 11-lb melanger running 72-hour cycles produces two batches a week; the same melanger running 36-hour cycles produces three or four. That's a real tradeoff for a solo maker with a wholesale book building up.

Three practical responses:

• Tune by SKU. Not every SKU needs 72 hours. House-blend bars often run beautifully at 36–48 hours; premium single-origin bars are where the extra time earns the most margin of flavor improvement.
• Add a second melanger before you shorten cycles. A second 11-lb Spectra costs about $3,200 and functionally doubles your throughput. Far better than compromising flavor to hit volume.
• Consider a dedicated conche only at real scale. A Selmi or Kreuzer conche makes sense when you're running 1,500+ bars a week and melanger queue is a real operational constraint. Below that, stick with stone melangers and longer runs.

Common questions

What's the minimum conching time for craft chocolate?

For a stone melanger, 24 hours is the absolute floor for bars you intend to sell commercially. Most experienced makers consider 36 hours the real minimum and run most production at 48 or longer. Under 24 hours is fine for testing and development, not for customers.

Can you over-conche?

Absolutely. Beyond about 72 hours, many bars start losing their delicate top-note aromatics. Industrial conches run 90+ hours intentionally to produce the homogenized, polished flavor of mass-market chocolate — which is the opposite of what most craft makers want. The signal for over-conching is loss of origin character and a flat, polished finish.

Does my stone melanger actually conche?

Yes. The stone-on-stone shearing continues to homogenize and agitate the chocolate long after particle reduction has stabilized, and the open surface (especially if the lid is off) allows volatile acids to escape. It's not as efficient as a dedicated conche at ventilating, but it works — and 145 years of bean-to-bar tradition has been built on exactly this combination.

Should I add lecithin?

Purely a matter of preference. Lecithin lets you achieve smoother mouthfeel with shorter conche times; it also slightly increases shelf life. Many purist craft makers skip it entirely in order to keep ingredient lists minimal — cacao, sugar, cocoa butter, nothing else. Both approaches produce excellent chocolate.

The cheat sheet

The single biggest flavor improvement most new craft chocolate makers can make is adding 12 hours to their melanger cycles. It costs nothing, requires no new equipment, and produces a measurable difference on every subsequent bar. Of all the variables in bean-to-bar production, conching time is the one where the expected improvement per hour of additional investment is highest.

For the broader production context, see our guides to the seven stages of bean-to-bar production and how to temper chocolate. For why well-conched chocolate tastes like “integrated” flavors in the first place, the answer lies upstream in our fermentation guide.