The Hershey’s Tropical Chocolate Bar was developed during World War II as a more palatable military chocolate bar for hot climates. It followed the infamous U.S. Army D Ration, also known as the Logan Bar, which was intentionally hard, bitter, and difficult to eat so soldiers would save it for emergencies.

The Tropical Chocolate Bar had a different goal.

It still needed to resist heat, but it was supposed to taste better than the original D Ration. In 1943, the Army asked Hershey to create a heat-resistant chocolate bar with improved flavor, and Hershey developed the Tropical Chocolate Bar for use in warm-weather and tropical environments. Hershey Archives notes that the bar was designed to hold its shape for one hour at 120°F.

This recipe recreates the 1943 WWII-era Tropical Chocolate Bar as closely as possible using the documented ingredient list and modern home-kitchen methods. It is not Hershey’s exact factory formula, which was not published as a household recipe. Instead, it is an authentic-style recreation based on the known ingredients, purpose, and texture of the wartime bar.

Recipe Information

Yield: 6 small bars or 3 larger bars

Prep Time: 20 minutes

Cook Time: 10 minutes

Cooling Time: 2–3 hours

Difficulty: Moderate

Recipe Type: Historical recreation

Era: WWII, 1943-style Tropical Chocolate Bar

Historical Accuracy Note

The documented 1940s Tropical Chocolate Bar ingredient list included:

• Chocolate liquor

• Skim milk powder

• Cocoa butter

• Powdered sugar

• Vanillin

• Vitamin B1

• Oat flour

This recipe focuses on that 1943 WWII-era formula.

Hershey later changed the formula in the late 1950s. That later version removed oat flour, replaced skim milk powder with nonfat milk solids, and replaced cocoa butter with cocoa powder.

This recipe is for the earlier wartime version.

Chocolate Liquor Clarification

Chocolate liquor is not chocolate liqueur.

Chocolate liquor, also called cocoa mass or cocoa paste, is pure ground cacao nibs. It contains cocoa solids and cocoa butter, but no alcohol.

For this recipe, use one of the following:

• Chocolate liquor

• Cocoa mass

• Cocoa paste

• Unsweetened baking chocolate

Unsweetened baking chocolate is the easiest grocery-store option for most home cooks. It is not meant to imply that Hershey’s factory formula used grocery-store baking chocolate. It is simply the most accessible retail form of the same basic ingredient.

Do not use Bailey’s, Godiva liqueur, crème de cacao, or any alcoholic chocolate drink. Chocolate liquor is chocolate. Chocolate liqueur is alcohol.

Ingredients

Chocolate Base

• 120 g unsweetened baking chocolate

• 40 g food-grade cocoa butter

  • Make sure you buy food-grade, as cocoa butter is normally sold as a non-edible cosmetic.

Dry Ingredients

• 110 g powdered sugar

• 60 g nonfat dry milk powder

• 15 g oat flour

• ¼ teaspoon vanillin powder or ½ teaspoon vanilla powder

  • Vanillin is the historically accurate ingredient, but hard and often expensive to find today.

Optional Historical Fortification

• Food-grade thiamine / Vitamin B1 powder, measured according to supplier directions

Equipment

• Kitchen scale

• Double boiler or heat-safe bowl over simmering water

• Mixing bowl

• Fine mesh sieve

• Silicone spatula

• Silicone chocolate bar molds or parchment-lined loaf pan

• Parchment paper

• Flat-bottomed measuring cup or small wooden block for pressing

Step 1 – Prepare the Dry Ingredients

In a mixing bowl, combine:

• Powdered sugar

• Nonfat dry milk powder

• Oat flour

• Vanillin or vanilla extract

• Optional Vitamin B1 / thiamine

Sift the dry ingredients if possible.

Whisk thoroughly until evenly blended.

This step is important because powdered milk, powdered sugar, and oat flour can clump. The smoother the dry mixture, the more even the final bar will be.

Step 2 – Melt the Chocolate Base

Set up a double boiler.

Add the following to the upper bowl:

• Unsweetened baking chocolate

• Cocoa butter

Warm gently over simmering water.

Stir often until fully melted.

Do not boil.

Do not allow water to splash into the chocolate.

The mixture should become smooth and glossy, but it will be thicker than ordinary melted chocolate.

Step 3 – Add the Dry Ingredients

Remove the melted chocolate from direct heat.

Add the dry mixture gradually, about one-third at a time.

Stir firmly after each addition.

The mixture will thicken quickly.

This is normal.

A Tropical Chocolate Bar recreation should not be thin and pourable like modern candy chocolate. It should become a dense chocolate paste.

If the mixture becomes difficult to stir, return it briefly to gentle heat and continue mixing.

Avoid adding water.

If absolutely necessary, add extra melted cocoa butter in very small amounts, about ½ teaspoon at a time.

Step 4 – Work the Mixture

Continue pressing and folding the mixture with a spatula until it becomes uniform.

The final texture should resemble a thick chocolate dough or stiff paste.

There should be no visible dry pockets of powdered milk, sugar, or oat flour.

This step is important because the original bar was commercially processed. A home kitchen cannot perfectly reproduce Hershey’s industrial equipment, so thorough hand mixing helps compensate.

Step 5 – Press Into Molds

Transfer the chocolate mixture into silicone bar molds or a parchment-lined pan.

Press firmly.

Use parchment paper and the bottom of a measuring cup, small wooden block, or spatula to compact the mixture.

Do not simply spread it loosely.

These should be dense ration-style bars, not soft brownies or fudge.

Aim for one of the following sizes:

• Six small 1-ounce bars

• Three larger 2-ounce bars

• One slab, later cut into portions

The Tropical Chocolate Bar was commonly produced in smaller one- and two-ounce portions, unlike the larger four-ounce D Ration.

Step 6 – Cool and Set

Let the bars cool at room temperature for 30–60 minutes.

Then refrigerate for 2–3 hours, or until fully firm.

Once hardened, remove from molds or lift the slab from the pan and cut into bars.

Allow the bars to return to cool room temperature before wrapping.

Step 7 – Wrap and Store

Wrap each bar tightly in parchment paper or wax paper.

For longer storage, place the wrapped bars in:

• Airtight containers

• Vacuum-sealed bags

• Mylar bags

Store in a cool, dry place.

For a historical-style presentation, wrap each bar in plain wax paper or parchment and place it inside a kraft-paper sleeve.

What to Expect

This should not taste like a modern Hershey bar.

A proper 1940s Tropical Chocolate Bar recreation should be:

• Firm

• Dense

• Mildly sweet

• More pleasant than a D Ration

• Less sweet than modern candy

• Slightly dry

• Chocolate-forward

• Somewhat milky

• Chewable, but still ration-like

The key difference between this and the D Ration is palatability.

The D Ration was designed to be emergency food.

The Tropical Chocolate Bar was designed to be heat-resistant chocolate that soldiers were more willing to eat.

Heat Resistance

The historical Tropical Chocolate Bar was designed to hold its shape for one hour at 120°F.

This homemade version should be more heat-resistant than a normal chocolate bar, but it may not perform exactly like Hershey’s wartime product.

That is because the original was made with commercial chocolate-processing equipment, controlled ingredient specifications, and industrial methods that are difficult to reproduce at home.

This recreation improves heat resistance by using:

• Chocolate liquor or unsweetened baking chocolate

• Added cocoa butter

• Powdered sugar

• Nonfat dry milk powder

• Oat flour

• Very little added moisture

For best results, keep the bars wrapped and store them away from direct heat or sunlight.

Estimated Nutrition

Nutrition will vary based on ingredient brands.

If divided into six small bars, each bar is approximately:

• Calories: 150–180

• Fat: 10–13 g

• Carbohydrates: 14–18 g

• Protein: 3–5 g

If divided into three larger bars, each bar is approximately:

• Calories: 300–360

• Fat: 20–26 g

• Carbohydrates: 28–36 g

• Protein: 6–10 g

Shelf Life

Because this recipe uses low-moisture ingredients, it should store better than most homemade chocolate desserts.

Estimated home storage:

• Pantry: 3–6 months

• Refrigerator: 6–12 months

• Freezer: 1 year or more

For best shelf life:

• Use cocoa butter, not dairy butter.

• Avoid liquid vanilla extract if possible.

• Keep water out of the chocolate.

• Wrap tightly.

• Store cool and dry.

• Vacuum seal for longer storage.

Discard the bars if they develop mold, a sour smell, rancid odor, unusual moisture, or an off flavor.

Historical Notes

The Hershey’s Tropical Chocolate Bar was created after the D Ration proved useful but unpopular.

The original D Ration had been designed as a dense emergency survival ration. It was hard, bitter, calorie-heavy, and intentionally not very enjoyable. That made sense for a last-resort ration, but it also created obvious morale and usability problems.

The Tropical Chocolate Bar was an attempt to preserve one of the D Ration’s most important strengths—heat resistance—while making the bar more acceptable to soldiers.

The 1940s version still used oat flour and Vitamin B1, along with chocolate liquor, skim milk powder, cocoa butter, powdered sugar, and vanillin.

The later 1950s version changed the formula, removing oat flour and replacing some ingredients. You can see our recipe for it here: Hershey’s Tropical Chocolate Bar Recipe (1957-1991)

D Ration vs. Tropical Chocolate Bar

The D Ration was the harsher emergency food.

The Tropical Chocolate Bar was the more usable military chocolate.

Optional Taste Adjustments

These adjustments move the recipe slightly away from strict historical recreation, but they can help home cooks tune the result.

Sweeter Version

Increase powdered sugar from:

• 110 g to 130 g

This makes the bar more pleasant and closer to a modern dark milk chocolate.

More Bitter Version

Reduce powdered sugar from:

• 110 g to 90 g

This makes the bar darker, firmer, and more austere.

Firmer Version

Add:

• 5–10 g oat flour

This makes the bar denser and more ration-like.

Smoother Version

Add:

• 5–10 g cocoa butter

This makes the mixture easier to work with and slightly smoother.

Serving Ideas

This is a historical ration recreation, not a dessert bar.

You can use it for:

• WWII food history tastings

• Camping

• Hiking

• Emergency food experiments

• Military ration comparisons

• Historical cooking projects

• Making children question their Halloween candy

Final Thoughts

The 1940s Hershey’s Tropical Chocolate Bar represents the next step after the D Ration.

The Army still needed chocolate that could survive high temperatures, but it also needed something soldiers were more willing to eat. The Tropical Chocolate Bar kept the military practicality of heat-resistant chocolate while improving flavor and usability.

This home recreation follows the known 1940s ingredient structure as closely as possible while clearly adapting the process for a modern kitchen.

It is not Hershey’s exact factory formula.

It is a practical, historically informed recreation of one of America’s most interesting wartime chocolate bars.