How Many Calories Are in an Acorn? Nutritional Breakdown Explained

January 12, 2026 •

4 min read

While squirrels are notorious for stockpiling acorns, many people are unaware that these nuts are also a viable food source for humans after proper preparation. In fact, ancient cultures across North America, Asia, and the Mediterranean regularly consumed acorns as a nutritious staple food. If you've ever wondered how many calories are in an acorn and what nutritional benefits they offer, the answer lies in their species and preparation method.

Quick Summary

This guide provides a comprehensive overview of acorn's caloric content and full nutritional profile. It details the preparation process to remove toxic tannins and outlines the safety precautions necessary for human consumption. Learn how to transform this wild food into a healthy and edible nut.

Key Points

High Caloric Content: A 100-gram serving of raw acorn meat contains approximately 387 calories, with the majority from fats and carbohydrates.
Tannin Removal is Crucial: Raw acorns contain bitter and potentially toxic tannins that must be leached out by boiling or soaking before they are safe to eat.
Sourcing Affects Nutritional Value: Calorie and nutrient content can vary based on the specific oak species and its growing environment.
Rich in Healthy Fats: Acorns contain a significant amount of healthy mono- and polyunsaturated fatty acids.
Versatile Culinary Uses: Properly processed acorns can be roasted, ground into gluten-free flour, or brewed into a caffeine-free coffee.
Freezer Storage is Recommended: Because acorn fats can go rancid, shelled acorns or flour should be stored in the refrigerator or freezer.

Understanding Acorn's Caloric and Nutritional Profile

Acorns are an energy-dense nut, with a single 100-gram serving of raw acorn meat containing approximately 387 calories. However, this figure is a general average; the exact caloric and nutritional content can vary significantly based on the species of oak tree. Different oak species produce acorns with different proportions of fats, carbohydrates, and proteins, affecting their overall caloric density. All acorns must be properly processed to remove bitter and toxic tannins before consumption.

The Macronutrient Breakdown of Acorns

The bulk of an acorn's energy comes from its fat and carbohydrate content. For a typical 100-gram portion of raw, shelled acorn meat:

Fat: Around 24 grams, consisting primarily of healthy monounsaturated and polyunsaturated fatty acids.
Carbohydrates: Roughly 41 grams, with a large portion being starch.
Protein: About 6 grams, although this can vary between species.

While acorns are not a primary source of protein compared to other nuts, they provide a well-rounded nutritional profile when prepared correctly. Their high fat and starch content historically made them a reliable source of sustained energy for indigenous populations.

The Importance of Leaching Tannins

Raw acorns contain high levels of tannins, bitter-ttasting compounds that are toxic in large amounts and can interfere with nutrient absorption. Leaching, a process of soaking or boiling acorns in water, is essential to remove these tannins. The process is complete when the water no longer turns dark brown. This makes the acorns safe to eat and significantly improves their flavor.

Hot vs. Cold Leaching Methods

There are two primary methods for leaching acorns, each suitable for different end products:

Hot Leaching:

Crack and shell the acorns.
Boil the acorn pieces in a pot of water for about 5 minutes.
Strain the acorns and replace the water. Repeat until the water runs clear.
This method is faster but can remove some starch, making it less ideal for baking.

Cold Leaching:

Grind the raw acorns into a coarse meal.
Place the meal in a container with cold water.
Change the water daily for several days or up to two weeks until the bitterness is gone.
This method preserves the starch, which helps the flour bind together for baking projects.

Comparison of Acorn to Other Common Nuts

To put the caloric content of acorns into perspective, it's helpful to compare them with other nuts (all values are approximate per 100 grams of raw, shelled nut meat):


Nutrient	Acorn (Raw)	Almond (Raw)	Chestnut (Raw)
Calories	387 kcal	579 kcal	131 kcal
Fat	24 g	50 g	2.2 g
Carbohydrates	41 g	22 g	27 g
Protein	6 g	21 g	3.2 g

As the table shows, acorns are moderately lower in calories than almonds but significantly higher than chestnuts due to their fat and carbohydrate content. This unique balance makes acorn flour an excellent gluten-free ingredient for baking, providing a distinct nutty flavor.

Health Benefits and Culinary Uses of Acorns

Beyond their caloric content, acorns are packed with beneficial nutrients and compounds. They are a rich source of vitamins (especially B-complex vitamins), minerals (including manganese, copper, and magnesium), and potent antioxidants. These antioxidants are known to help protect cells from damage caused by free radicals.

Once leached and dried, acorns can be used in a variety of culinary applications:

Roasted snack: Seasoned and roasted acorns make a hearty, crunchy snack.
Acorn flour: Ground into a gluten-free flour for use in bread, pancakes, or pastries.
Acorn coffee: Roasted, ground acorns can be used as a caffeine-free coffee substitute.
Added to dishes: Whole or chopped acorns can be added to stews or porridges.

Sourcing and Storing Acorns Safely

Foragers should ensure they are harvesting from a reliable location away from heavy pollutants and that the acorns are ripe. Signs of a ripe acorn include a brown color and the cap being easily removable. After collection and processing, dried acorns can be stored in an airtight container in a cool, dark place for several years. However, once shelled or ground, the meal and flour should be stored in the refrigerator or freezer due to the risk of the fats turning rancid.

The Takeaway

In conclusion, acorns offer a substantial number of calories and a wealth of nutrients, making them a valuable food source with a rich history. By understanding the need for proper preparation and recognizing the differences between oak species, foragers can safely and effectively incorporate this wild edible into their diet. The calorie count of approximately 387 kcal per 100 grams for raw acorn meat highlights its potential as a dense, nutritious food source when leached and prepared for consumption.

For a detailed look at wild foraging and identification, a fantastic resource is the USDA's guide on identifying different oak species.

Frequently Asked Questions

No, you should not eat raw acorns. They contain high levels of bitter and toxic tannins that can cause digestive upset and liver damage in large amounts. They must be leached with water before consumption.

Acorns are prepared by leaching to remove tannins. You can either boil shelled acorns in multiple changes of water until the water runs clear (hot leaching) or soak ground acorn meal in cold water, changing it daily (cold leaching).

The calorie count for a single acorn is highly variable depending on its size and species. However, a single ounce (28 grams) of raw acorn meat contains about 110 calories.

While acorns contain protein, at around 6 grams per 100-gram serving, they are not considered a primary protein source compared to other nuts like almonds. They are richer in carbohydrates and fats.

Species from the 'white oak' group, such as the American white oak, tend to have the least bitter acorns and therefore require less leaching. However, bitterness can vary significantly even within the same species.

Acorns are significantly higher in calories than chestnuts. A 100-gram serving of raw acorn has approximately 387 calories, while the same amount of raw chestnuts has about 131 calories.

Yes, properly leached and dried acorn flour can be used for baking. Since it is gluten-free, it is often best to combine it with other flours to help with binding and texture.