Alum Blocks For Wet Shaving (How To Use Them And Why)

I still remember a gift a colleague gave me while on a business trip to Hong Kong—an alum block. I didn't know what it was at the time or how to use an alum block, but it proved to be one of the most useful gifts for traditional wet shaving I've ever gotten.

I've since learned that achieving the perfect shave is all in the follow-through. Although it could be easily overlooked, the post-shave routine is just as important as the shave itself, and the alum block is an essential part of that.

What Is An Alum Block?

An Alum Block is a crystal-like stone in the shape of a miniature bar of soap, also known as an alum stone or alum crystal, a mineral block made from potassium alum, a naturally occurring mineral and composite known for its antiseptic and astringent properties.

Historically used by the ancient Egyptians, potassium alum was used more than 4,000 years ago for its antiseptic and healing properties and to cool and revitalize the skin.

Available in different shapes and sizes, such as an alum bar or crystal, there are convenient travel-size alum sticks for precise application.

The alum bar today is utilized as a wet shaving essential in the post-shave process to cool and refresh the skin after shaving wetted with water and gently rubbed over the shaved area to minimize redness and soothe irritation, limit the appearance of razor bumps, fight razor burn, and heal minor nicks and cuts.

Because of their antibacterial properties, alum blocks can even tighten pores, kill surface bacteria, and reduce pimples and acne.

The History Of  The Alum Stone

It seems to be true that people have almost always sought better therapeutic remedies. In addition to being found at many archaeological sites in Egypt, the mineral block has also been discovered in sites that suggest they were also used in Ancient Greece and Rome.

The original alum block enthusiasts were actually the ancient Egyptians. More than 4,000 years ago, the Egyptians came to discover the antiseptic and healing properties of the mineral. Although our image of the ancient Egyptians might not necessarily align with a concern for a hedonistic pursuit of comfort or vanity, they knew that the alum block felt really good and cooled their face in the heat. That's all it took for the practice to become commonplace.

The Ancient Greek historian Herodotus wrote that Egyptian alum was a valuable commodity back in his day. Similarly, the Ancient Roman historian and army commander Pliny the Elder documented that the Romans used the substance in their medicine and for dyeing fabrics. During the Islamic middle ages, alum was used extensively as a "mordant"—a chemical that helps dyes set into fabrics.

What Is Alum Used For?
The Benefits & Uses of An Alum Block

Alum (aluminum potassium sulfate) is mineral block that acts as a natural coagulator, astringent and antiseptic. The alum block is a versatile therapeutic treatment used to eliminate all kinds of undesirable shaving and related skin problems. Such as:

• Increase grip on slippery safety razors or straight razor handles
• Treat small nicks and cuts
• Fight razor burns
• Improve skin tone
• Reduce skin inflammation
• Address post-shaving related skin irritation
• Reduce the appearance of razor bumps
• Heal minor bleeding by constricting blood vessels and tightening pores
• Replace your favorite scented deodorant
• Clear up pre-existing skin conditions like acne or spotty skin for a better appearance
• Reduce the risk of developing ingrown hairs
• Calm the skin and avoid razor bumps for women after waxing sensitive areas

When using an alum block, you'll find it tightening pores and constricting blood vessels to do its job. It's a coagulant that thickens blood cells to stop bleeding and simultaneously has a soothing, cool, refreshing sensation on the skin. It also kills surface bacteria.

Surprising as it may be, alum's versatility doesn't stop there: It's also a great natural deodorant. It's probably not a better first-choice than your favorite scented deodorant, but all those crystal deodorants in the store are just slightly refined versions of a pure alum block.

The crystals come in different shapes and sizes. You can get a big block if you're just using it at home as part of your regular shaving routine, but you can also get a smaller bar for travel or a more precise application.

The type of razor you use to shave doesn't affect the post-shave routine. An alum block should be part of every traditional wet shaving kit, regardless of the razor you choose.

How To Use An Alum Block

Step 1: After you finish shaving, wash your face to clear any remaining soap or shaving cream residue. Splash your face with cold water. This helps to close and tighten pores and allows the alum block to easily glide over your face. Just gently rubbing the wet alum block on your skin will lightly exfoliate your pores.

Step 2: Wet the alum block with cold water before applying it to your face. Make sure the entire surface is wet. 

Pro tip: You can soak an alum block in ice water before you use it for an increased cooling sensation—especially if you're prone to nicks, cuts, or razor burn. Or if the razor blade wasn't as sharp as you would've liked, if this is the case you might want to revisit our previous post on how often should you change your safety razor blade.

Step 3: Massage the block gently across the areas of your neck and face that you shaved. Rub gently because of its astringent qualities, and you should expect to feel a bit of tightness and tingling or a mild burning sensation. This is expected; it's just the alum crystal and the salicylic component of natural potassium alum doing its magic. 

*If you have sensitive skin do not leave alum block on for more than 20 seconds.

Let the alum residue sit on your skin for about 15 to 20 seconds—roughly the same amount of time it takes to sing Happy Birthday twice or the ABC song. This allows the crystals to shrink your pores and sanctify your skin. Then rinse the residue off with cold water.

Step 5: Apply moisturizer to your freshly shaved skin and apply an aftershave balm or aftershave product as needed such as a high-quality moisturizing cream, aftershave, or shave balm with natural ingredients.

Pro tip: One of my favorites to cool razor burn and for a true cold shock is to use Barrister and Mann terror aftershave.

Alternatives To Alum Blocks For Wet Shavers:
The Styptic Pencil