Calcium chloride dihydrate CAS 10035-04-8

I. What is Calcium Chloride Dihydrate (CAS 10035-04-8)?

II. Uses of Food-Grade Calcium Chloride

2.1 Canned tomatoes and vegetables – a "calcium skeleton" that won't collapse after 121°C sterilization.

This is the most common single application of E509 in the global food industry—tens of thousands of tons of CaCl₂ dihydrate are used annually for the solidification of canned vegetables and fruits.

The "destructive" principle of canned sterilization

After harvesting, the natural pectin methyl esterase (PME) in the cell walls of vegetables and fruits continues to work, hydrolyzing the methyl ester groups in pectin into free carboxyl groups (-COO⁻). These negatively charged carboxyl groups are normally "cross-linked" in plant cells by the natural Ca²⁺ concentration—forming calcium-pectin gels—and this calcium bridge is the molecular basis for the rigidity and fragility of vegetable cell walls. However, the natural Ca²⁺ concentration is low—insufficient to resist pectin hydrolysis during high-temperature sterilization (121°C).

Vegetables are heated to kill bacteria → pectin chains break down + calcium bridges disintegrate → cell walls collapse → vegetables become soft and mushy.

The "calcium lock" mechanism of calcium chloride

If vegetables are soaked in a dilute CaCl₂ solution (0.05%-0.5%) for 530 minutes before sterilization—or CaCl₂ is added directly to the broth for canning—the extremely high concentration of Ca²⁺ in the solution rapidly penetrates the vegetable tissue—forming a dense calcium cross-linking network with the free carboxyl groups released by pectinase in the cell walls.

This calcium cross-linking network is denser than natural pectin calcium bridges—because the additional Ca²⁺ "pins" each newly cleaved cross-linking site. During high-temperature sterilization—random breakage of the pectin backbone still occurs—but the broken fragments are tightly fixed in the cell wall matrix by countless calcium bridges—the skeleton is broken but not dislodged—and the vegetable maintains its shape and firmness macroscopically.

2.2 Molecular Gastronomy – Calcium Source Selection for Reverse Spherical Baths

In molecular gastronomy, basic spherification and reverse spherification involve cross-linking of Ca²⁺-containing liquids with sodium alginate solutions on the surface of droplets to form elastic gel films that shape liquid inclusions into "caviar" shapes.

The chemical logic of positive spherization vs. anti-spherization

sphericity

● Juice containing sodium alginate is dropped into a CaCl₂ bath—Ca²⁺ diffuses from the outside in—calcium alginate gel forms from the outside in—the outer layer is gel, and the inner layer remains liquid. The drawback is that the timing of stopping the cross-linking must be precise (otherwise, Ca²⁺ will continue to diffuse into the droplet—eventually hardening into a rubber ball—without the "bursting" effect).

Anti-spheric

● Fruit juice containing CaCl₂ or calcium gluconate is dropped into a sodium alginate bath—Ca²⁺ diffuses from the inside out—calcium alginate gel forms from the inside out—outer layer gel, inner layer liquid. The advantages of anti-spheroidization are—after the droplet leaves the sodium alginate bath—the gelation reaction stops (there is no more sodium alginate outside the bath for cross-linking)—it avoids "over-gelling"—and makes it easier to control the thin shell and bursting effect.

CaCl₂ vs. Calcium Gluconate: A Calcium Source Game in Anti-Globular Baths

Specific operating parameters for CaCl₂ in molecular gastronomy

2.3 Cheese Making – The “Calcium Revitalizer” for Curd

When pasteurized milk is used in cheese production, approximately 5% to 20% of the soluble calcium precipitates from the ionic state to insoluble calcium phosphate during the pasteurization process. This portion of calcium no longer participates in the activation of rennet and the stabilization of casein micelles.

The Triple Chemical Role of CaCl₂ in Cheese Curd

CaCl₂ addition guidelines for cheese

Important Note: The CaCl₂ solution must be added to the milk before adding the rennet. If the rennet is added first, followed by CaCl₂, curdling will begin, resulting in uneven calcium ion distribution and a non-uniform curd with a layered internal structure (a hard outer layer and a soft inner layer). The correct order is: Heat the milk to curdling temperature → Add the diluted CaCl₂ solution and stir well → Let stand for 5 minutes to allow calcium ions to fully balance → Add the rennet.

2.4 Brewing – Beer and Water Adjustment

In beer brewing, Ca²⁺ is the most important hardness cation in brewing water. CaCl₂ dihydrate is used for:

Lowering the pH of the mash: Ca²⁺ reacts with phosphate in the malt to release H⁺, thus lowering the wort pH to the optimal range for α-amylase (pH 5.2~5.4).

Promotes protein coagulation: During the wort boiling stage, Ca²⁺ helps heat-denatured proteins in the wort aggregate into larger flakes (Hot Break / Trub) that can later be precipitated or filtered out, resulting in clearer beer;

Yeast flocculation: After fermentation, Ca²⁺ promotes the aggregation and sedimentation of yeast cells, making it easier for beer to separate from the yeast sludge and reducing filtration pressure.

CaCl₂ (which lowers pH) and CaSO₄ (which does not affect pH and provides the "dry" taste of SO₄²⁻) are two calcium source levers in the hands of winemakers—the amount of CaCl₂ used is usually in the range of 0~150 mg/L (calculated as dihydrate CaCl₂).

2.5 Calcium Fortification – Beverages and Condiments

The limitations of CaCl₂ in calcium fortification: its bitter and salty taste cannot be completely masked in clear and low-salt beverages—this is its fundamental disadvantage in this scenario. E509's role as a calcium fortifier is limited to foods that are "already salty"—salty soups, sauces, marinades—in which the slight saltiness and bitterness of the additional calcium salt are highly diluted by the overall flavor—and cannot be perceived independently by the consumer.

2.6 Prevention of hardening in canned beans – a role completely opposite to that of hardeners

Surprisingly, in some foods, CaCl₂ acts in the exact opposite way to a hardening agent—it doesn't "make the food harder," but rather "prevents bean skins from hardening after canning."

In the canning of certain beans (such as chickpeas and white beans), natural pectin gradually forms calcium bridges with Ca²⁺ and Mg²⁺ during storage, making the bean skin hard and tough—a common customer complaint known as "stone bean skin." Limiting the concentration of free calcium in the soaking solution can actually inhibit further hardening during storage. In this scenario, the process either avoids adding CaCl₂ or uses chelating agents (such as EDTA or citrate) in the soaking bath to complex away the Ca²⁺ naturally present in the raw materials and water—to prevent hardening.

III . Summary

Calcium Chloride Dihydrate (food grade calcium chloride dihydrate / CAS 10035-04-8) in the food grade can be summarized in four words: safe and effective.

Safety—Unlike anhydrous CaCl₂, it does not release heat violently upon contact with water, pose a risk of burns to skin and mucous membranes, or generate thermal stress on stainless steel equipment. It can be weighed and dispensed directly by food workers under ordinary work gloves.

Effective—its solubility is about 700 times that of calcium sulfate—Ca²⁺ penetrates deep into vegetable tissue within tens of seconds—the entire calcium bridge is established before the sterilizer door is closed. In cheese curd—it evenly distributes Ca²⁺ in the milk 5 minutes before rennet is added—as soon as rennet appears—calcium is already there waiting.

Its bittersweetness—a threshold it can never cross in beverages and clear foods. But in canned vegetables and cheese curds, the two most crucial scenarios for it—the bittersweetness is completely diluted by the salted broth, the sweet and sour tomatoes, and the creamy cheese—it becomes imperceptible. It leaves only calcium bridges—the vegetables are crisp, the curds are hard, and the molecular gastronomy pearls are locked in a thin shell in a sodium alginate bath.