Old Bottles Identification: Expert Guide to Dating & Valuing Antique Glass

Bottle collecting has grown significantly in popularity in recent years, with enthusiasts searching for rare examples from the 19th and early 20th centuries. The appeal lies not only in the aesthetic beauty of these glass vessels but also in their historical significance. Every bottle tells a story about manufacturing processes, consumer habits, and cultural trends of its era.

Whether you’re a seasoned collector or someone who has just discovered an interesting old bottle, understanding how to properly identify and date these artifacts will help you appreciate their true value and historical context.

Made without molds, these bottles feature irregular shapes, asymmetrical features, and pontil marks on the base. Each is unique, as they were individually crafted by glassblowers.

Created in sectional molds that left distinct seam lines. Typically, seams run up the sides and around the shoulder but not through the neck and lip, as these parts were still hand-finished.

Bottles from this period show mold seams that extend up the neck but stop before the lip. The top was still applied by hand, creating a distinct tooled finish.

After the Owens Automatic Bottle Machine became widespread, bottles display mold seams running all the way through the lip. Mass production standardized shapes and eliminated many hand-finishing characteristics.

Mold Seams and Manufacturing Marks

The height and appearance of mold seams are crucial for dating bottles. As described by Gozone Pack, between 1905-1920, glass bottles had thicker and higher seams. After 1920, with fully automatic production, seam lines run completely from the base through the lip.

Pontil Marks

A pontil mark is a rough or smooth scar on the base of a bottle where the pontil rod was attached during production. According to the Society for Historical Archaeology, these marks are typically found on bottles made before 1860. Their presence almost certainly indicates a bottle of considerable age and potentially higher value.

Base Markings

Many antique bottles feature manufacturer marks, numbers, or symbols on their bases. The Antique Trader notes that these trademarks usually appear on the bottom of the bottle, possibly on the label, and sometimes embossed on the face or side. These markings can be cross-referenced with manufacturer databases to determine origin and approximate age.

According to the Society for Historical Archaeology’s Bottle Typing Guide, the shape of a historic bottle is usually indicative of what it contained. Here are some common bottle types and their original purposes:

Color and Its Significance

The color of antique glass bottles can help narrow down both age and type. According to bottle identification guides, certain colors were prevalent during specific periods:

• Aqua: Common in bottles from the 1800s to early 1900s
• Amber/Brown: Primarily used for beer and medicine bottles to protect contents from light
• Dark Olive Green: Often seen in early wine and champagne bottles
• Cobalt Blue: Less common, often used for medicine and poison bottles
• Purple/Amethyst: Clear glass that turned purple from exposure to sunlight (contains manganese, common from 1880-1914)
• Black Glass: Actually very dark green or amber, common in early alcoholic beverage bottles

As noted by True Legacy Homes, bottles that have turned purple from sun exposure typically date between 1880 and 1914, when manganese dioxide was used as a clarifying agent in glass production.

Manufacturer’s Marks

The Society for Historical Archaeology’s Makers Marks Page provides an extensive database of manufacturer marks found on bottles. These marks typically appear on the bottle’s base and can include:

• Initials or full names of glass companies
• Symbols or logos
• Location indicators
• Date codes or patent numbers

For example, bottles marked with “OWENS” or an “O” in a square indicate production by the Owens Bottle Company, which operated from 1911-1929.

Embossed Product Information

Many antique bottles feature embossed text that identifies:

• Product names: “Dr. Kilmer’s Swamp Root” or “Coca-Cola”
• Manufacturer claims: “Warranted Flask” or “Guaranteed Pure”
• Place of origin: “New York” or “San Francisco”
• Content volume: “One Quart” or “16 OZ”

These embossed details not only help identify the bottle but often make certain examples more collectible, especially with unusual claims or regional significance.

Dating Codes and Numbers

According to Whiskey ID, many bottle manufacturers molded the year into the glass at the bottom in 2-digit format, often found in the lower right portion when examining the base. This practice became particularly common after 1930.

Condition Factors

The condition of an antique bottle dramatically affects its value. According to bottle collecting forums like Antique Bottles Forum, collectors assess condition based on these key factors:

1. Damage: Chips, cracks, and flakes significantly reduce value
2. Staining: Mineral deposits or “sick glass” (etching from burial)
3. Clarity: Cloudiness or haziness from content residue or environmental exposure
4. Original Closures: Presence of original stoppers, corks, or caps increases value
5. Label Condition: If present, intact original labels can substantially increase value
6. Cleanliness: Proper cleaning without damage to patina

Rarity Considerations

Rarity is determined by several factors that bottle collectors should consider:

1. Production Quantity: Limited production runs create scarcity
2. Survival Rate: Some types were commonly discarded or had high breakage rates
3. Regional Distribution: Bottles with localized distribution can be highly sought after
4. Time Period: Generally, older bottles (pre-1870) are rarer due to limited survival
5. Unusual Features: Distinctive colors, shapes, or manufacturing errors can create rarity

As noted by Yahoo’s article on valuable bottles, bottles suspected of high value should be professionally appraised, as experts consider market trends, condition, manufacturer, material, and desirability when establishing prices.

According to Antique Advertising’s bottle guide, these categories tend to be most sought after by serious collectors:

Historical Flasks

Patriotic and historical flasks from the 1820-1870 period feature detailed molded designs of eagles, presidents, and historical scenes. These highly collectible bottles can command prices from several hundred to tens of thousands of dollars for rare examples.

Bitters Bottles

Bitters were medicinal alcoholic preparations sold as health remedies in the 19th century. Their distinctive shapes (often figural or cabin-shaped) and beautiful amber or green colors make them highly collectible, with prices ranging from $100 to $15,000+ for rare examples.

Colored Glass Bottles

Bottles in unusual or rare colors can command premium prices regardless of their original purpose. Certain colors like cobalt blue, deep amethyst, yellow amber, and true red are particularly desirable. Some rare-colored historical flasks have sold for over $50,000.

Regional Soda and Beer Bottles

Early soda and beer bottles from the mid-to-late 19th century, especially those with strong local connections to small towns or short-lived companies, can be highly valuable to collectors focusing on specific regions or brewing history.

Poison Bottles

Distinctive poison bottles with their textured surfaces, unusual shapes, and often cobalt blue or green colors were designed to be identifiable by touch in dark medicine cabinets. Their unique appearance makes them popular with collectors, with prices ranging from $50 to several thousand dollars.

Essential Reference Materials

According to collector forums, these references are considered essential for serious bottle identification:

1. Antique Trader Bottles Identification & Price Guide - As noted on Amazon, this is the only full-color bottle book on the market, with more than 5,000 listings and 700 photographs covering over 50 bottle categories.

2. The Historic Bottle Website - SHA.org’s bottle website is a comprehensive free resource created by the Society for Historical Archaeology, offering detailed information on dating, typing, and identifying historic bottles.

3. Specialty collector guides - Many collectors focus on specific types of bottles (medicine, soda, beer) and use specialized guides for those categories.

Digital Identification Tools

Many collectors now use digital tools to help identify bottles:

1. Online databases - Websites like SHA.org maintain searchable databases of bottle marks and manufacturers.

2. Mobile apps - Various bottle identification apps allow collectors to search databases or connect with experts by uploading photos.

3. Collector forums - Sites like Antique-Bottles.net allow collectors to share knowledge and get identification help from experienced collectors.

Physical Examination Tools

For detailed examination of bottles, these tools are recommended:

1. Jeweler’s loupe or magnifying glass - For examining small maker’s marks and identifying manufacturing details

2. LED flashlight - For illuminating the interior of bottles and highlighting flaws or features

3. Digital calipers - For precise measurement of heights, diameters, and other dimensions

4. UV light - For detecting glass composition changes that might indicate age (manganese glass will fluoresce under UV)

The most comprehensive free resource for historic bottle identification, with detailed sections on bottle dating, typing, and manufacturer marks.

Active community of bottle collectors sharing knowledge, identification help, and market information. The thread archives contain valuable information on thousands of bottle types.

The definitive print reference with over 5,000 bottle listings and 700 color photographs covering all major bottle categories from the 19th and 20th centuries.

Free online price guide with descriptions and values for various categories of antique bottles and jars, with high-quality images.

Detailed article explaining key techniques for determining the age of antique glass bottles, with visual examples and manufacturing history.

Comprehensive guide to bottle shapes and their original purposes, helping to identify what different bottle styles were originally used for.

Finding Antique Bottles

According to experienced collectors on forums like Reddit’s r/BottleDigging, bottles can be acquired through various channels:

1. Bottle digging - Research and excavate old dump sites, privies, and abandoned building foundations (always obtain proper permissions)

2. Estate sales and auctions - Often yield interesting bottles from established collections

3. Antique shops and flea markets - Common sources for moderately priced bottles

4. Online marketplaces - eBay, Etsy, and specialized collector sites offer vast selections

5. Bottle shows and collector meets - Excellent for finding quality pieces and networking with other collectors

Proper Cleaning Techniques

Proper cleaning is essential but must be done carefully to avoid damage:

1. Soak in warm, soapy water - For bottles with minimal dirt
2. Use soft brushes for internal cleaning - Bottle brushes or cleaning beads can help
3. Avoid harsh chemicals - These can damage glass patina
4. Clean stoppers and closures separately - Use appropriate methods for cork, glass, or metal components
5. Air dry completely - Prevent water spotting by thorough drying

Display and Preservation

To showcase and protect your collection:

1. Use appropriate shelving - Glass shelves with subtle lighting highlight bottle features
2. Protect from direct sunlight - UV light can damage or change glass color over time
3. Control humidity - Extreme conditions can affect labels and closures
4. Document your collection - Keep records of each bottle’s history, purchase date, and value
5. Consider insurance - For valuable collections, specialized insurance may be appropriate

Focused Collecting Strategies

Most successful collectors advise focusing collection efforts rather than acquiring randomly:

1. Regional focus - Bottles from a specific city or state
2. Type focus - Specialize in medicine, soda, ink, or other specific bottle types
3. Era focus - Concentrate on bottles from a specific time period
4. Color focus - Collect bottles in a particular color or range of colors
5. Manufacturer focus - Collect bottles from a specific glass company

The most reliable method for identifying old bottles involves examining several key features:

1. **Base markings**: Look for manufacturer logos, numbers, and symbols on the bottom
2. **Mold seams**: The height and appearance of seam lines indicate production era
3. **Lip finish**: How the top was formed (applied by hand or machine)
4. **Pontil mark**: A scar on the base indicates pre-1860s production
5. **Embossing**: Text and designs molded into the glass
6. **Color**: Certain colors were prevalent in specific eras
7. **Shape**: Bottle shapes often indicate their original purpose

For the most accurate identification, consult reference books or the [Society for Historical Archaeology's bottle website](https://sha.org/bottle/).

Dating antique bottles relies on manufacturing characteristics that evolved over time:

1. **Mold seams**: Their height indicates approximate age; seams running completely through the lip typically indicate post-1910 production
2. **Base markings**: Many manufacturers included date codes (especially after 1930)
3. **Pontil marks**: Presence indicates pre-1860s production
4. **Color**: Certain glass colors were used during specific periods (purple glass from manganese dioxide typically dates 1880-1914)
5. **Manufacturing method**: Free-blown (pre-1860s), mold-blown with applied finish (1860s-1910s), or machine-made (post-1910)
6. **Embossing style**: Certain typography and designs were used in specific eras
7. **Maker's marks**: Can be cross-referenced with manufacturer databases

As noted by [Whiskey ID](https://whiskeyid.com/how-to-date-id-your-whiskey/), many bottle manufacturers molded the year into the glass at the bottom in 2-digit format, often found in the lower right portion.

Determining the value of antique bottles requires considering several factors:

1. **Consult price guides**: References like the Antique Trader Bottles Identification & Price Guide provide value ranges
2. **Check online auction results**: Sites like eBay (completed listings) show real market values
3. **Join collector forums**: Communities like [Antique-Bottles.net](https://www.antique-bottles.net/) often help with valuations
4. **Attend bottle shows**: Compare similar bottles and speak with dealers
5. **Get professional appraisals**: For potentially valuable bottles, professional appraisal is recommended

As [Yahoo's article](https://www.yahoo.com/lifestyle/10-old-bottles-worth-money-103000489.html) notes, professional appraisers consider factors like market trends, condition, manufacturer, material, desirability, and rarity when establishing values.

Liquor bottles have specific dating features:

1. **Glass date codes**: As noted by [Bourbon Sippers](https://bourbonsippers.com/whiskey-bottle-dates/), many liquor bottles have two-digit embossed numbers on the bottom corresponding to the year (e.g., 99 for 1999)
2. **Tax stamps**: If present, U.S. tax stamps changed design over the years and can help date the bottle
3. **Label designs**: Liquor brands updated label designs periodically
4. **Bottle technology**: Manufacturing features like seams and base markings apply to liquor bottles as well
5. **Government warnings**: Mandatory warning labels were introduced at specific times
6. **UPC codes**: Their presence indicates post-1980s production

For collectible whiskey bottles in particular, bottle shape, label design, and tax stamps are especially useful for dating.

The value of old bottles varies tremendously based on several factors:

1. **Rarity**: Uncommon bottles command higher prices
2. **Age**: Generally, pre-1900 bottles are more valuable
3. **Condition**: Mint condition bottles with no damage are worth significantly more
4. **Color**: Unusual colors (cobalt blue, true red, yellow) often command premiums
5. **Historical significance**: Bottles with important historical connections are more valuable
6. **Embossing/design**: Elaborate embossing or unique designs increase value
7. **Collector interest**: Current collecting trends affect prices

While many common bottles might be worth only $5-20, rare examples can sell for thousands or even tens of thousands of dollars. Historical flasks, rare bitters bottles, and certain colored glass bottles tend to be most valuable.

Several apps and online tools can help with bottle identification:

1. **Google Lens**: Can match bottle images with similar examples online
2. **Collector apps**: Some specialty apps focus on bottle identification
3. **Online forums**: Not apps per se, but sites like Reddit's [r/BottleDigging](https://www.reddit.com/r/BottleDigging/) allow uploading photos for expert identification
4. **Auction house apps**: Some major auction platforms have identification features

However, no app currently provides comprehensive bottle identification with complete accuracy. Most collectors still rely on reference books, websites like the [SHA Bottle Website](https://sha.org/bottle/), and consultation with experienced collectors for definitive identifications.

A pontil mark (or scar) appears on the base of a bottle and indicates hand-blown production, typically pre-1860s. Pontil marks come in several varieties:

1. **Open pontil**: A rough, circular scar with sharp edges
2. **Sand pontil**: A grainy, sandpaper-like texture in a circular area
3. **Iron pontil**: A smooth, often reddish or graphite-colored deposit
4. **Improved pontil**: A smoother variant with less pronounced scarring

The presence of any pontil mark usually indicates a bottle of considerable age and potentially higher value. The [SHA Bottle Bases page](https://sha.org/bottle/bases.htm) provides detailed images and descriptions of different pontil types.

The purple coloration in old clear glass bottles is caused by a chemical reaction:

1. **Manganese dioxide**: From approximately 1880 to 1914, glassmakers added manganese dioxide to glass batches as a decolorizing agent to produce clear glass
2. **Sunlight exposure**: When exposed to ultraviolet light for extended periods, the manganese in the glass undergoes a chemical reaction
3. **Color change**: This reaction causes the clear glass to gradually turn varying shades of purple or amethyst
4. **Dating significance**: The presence of this "sun-purpled" glass typically indicates production between 1880 and 1914

As noted by [True Legacy Homes](https://www.truelegacyhomes.com/age-glass-bottles/), this purple coloration helps date bottles to this specific period. After World War I, manganese (which was primarily sourced from Germany) was replaced with selenium as a glass decolorizer, which does not produce the purple effect.

Whether you’re just beginning your collecting journey or are a seasoned enthusiast looking to refine your identification skills, the resources and techniques shared in this guide provide a solid foundation for exploring the fascinating world of antique bottles. From pontil-marked medicines of the mid-19th century to machine-made sodas of the early 20th century, each bottle represents a unique chapter in our material culture history.

As you develop your expertise, remember that bottle collecting is as much about preservation and historical appreciation as it is about ownership. By properly identifying, documenting, and caring for these glass treasures, collectors play an important role in preserving industrial and commercial history for future generations.

Happy collecting, and may you find that rare and special bottle that has eluded collectors for years!