The latest news from American Glass Research.

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Volume 6 / Issue 4

Do you know why some old glass bottles and windows look purple?

Glass naturally has a greenish tint due to iron impurities in sand. To make perfectly clear glass, decolorizing agents are added to offset the green color from iron. Up to the first half of the 20th century, glass makers frequently used manganese dioxide, which has a pinkish hue.  When manganese-bearing glass is exposed to UV rays from the sun over the course of weeks or years, the manganese changes oxidation state and takes on a darker purple color. The piece of purple glass shown here is from an old, broken bottle found at a campsite on top of a mountain in Maine. Modern container glass manufacturers typically use selenium and cobalt as decolorizing agents instead of manganese.


Strong demand leads to 2nd printing of New Color Atlas of Defects

Based on strong demand the new Color Atlas of Glass Container Defects has been reprinted and is available to order. This photographic guidebook is for manufacturers, fillers, and trade suppliers and can help to quickly identify and resolve defect problems.

The Atlas delivers a common lexicon for understanding defects that often go by several names in different industry sectors. With over 450 original photographs on 154 pages it provides detailed descriptions of 65 defects that occur in container glass. Appendices include diagrams of the parts of glass containers as well as a glossary of glass defect terminology. 

This volume focuses on defects related to molded glass containers used in the food, beverage, and pharma industries. Defects specific to tubing vials are also included due to their importance in pharmaceuticals. 

The cost is $225.00 USD, which includes sales tax or 225 Euros excluding VAT in Europe. The book is available directly from AGR or on Amazon.  Contact Us directly to reserve your copy, call us at +1-724-482-2163 or email Linda Pilosi: or in Europe Jennifer J. Hu-a-ng:

New AGR Capabilities Brochure

Our new 16 page AGR Capabilities Brochure is now available showing the wide range of AGR services to help you with your breakage issues, container designs, training, auditing and glass quality/composition.

Download a digital version HERE or Contact Us to receive a printed copy.


What causes “skunky” beer?

 In 1944, the industry was not sure why the taste of beer at times became “skunky”.  So a series of tests were undertaken at Preston Laboratories to determine  if the color of a beer bottle could prohibit the creation of the objectionable taste.   They looked at flint, amber and green bottles and conducted taste testing under carefully controlled conditions (it must have been a tough job but someone had to do it).

Sound interesting?  You can read the study conducted by our founder Dr. Frank Preston in the recently released Legacy Technical Paper entitled “Development of Distasteful Flavor in Beer”. Click HERE to download.

Did you know... Glass can be flexible?

We demonstrate this property in our Training Seminars using a paneled flask with a capillary tube inserted through a stopper and put into the finish of the bottle.  When the container is squeezed across the flat sidewall, the glass deforms inward, reducing the volume of the flask and forcing the liquid to rise in the capillary tube.  When the squeeze force is removed, the glass returns to its original shape and the liquid falls back to its starting position. Thus, demonstrating the elastic properties of glass and how it can exhibit flexibility.
If you have questions about your glass, do not hesitate to Ask Our Experts.
2020 Training Seminar Schedule Announced

Do you want to learn how to diagnose and prevent bottle breakage? Conduct a thorough audit of a glass manufacturing plant? Or understand all the implications of Lightweighting a bottle design?

AGR Training seminars can help in all these areas and will be held in the first half of the year in Krakow, Poland, Munich/Lake Ammersee, Germany, Butler, PA, Montecchio, Italy and Wuxi, China. 

Here is our first quarter schedule:
February 11-12 Krakow: Audit of Glass Plant Operations
February 13-14 Krakow: Evaluation and Lightweighting of Glass Container Designs
March 10-13 Munich/Lake Ammersee: Fracture 3: Master Class
March 16-18 Munich/Lake Ammersee: Fracture1: Testing and Breakage Diagnosis of Glass Containers

See our Training Schedule for the dates and locations of all of our seminars and our Training Catalogue for descriptions of all of our seminars as well as registration.

Contact Us if you would like to set up an appointment.
American Glass Research
603 Evans City Road, Butler, PA 16001
Tel: +1 (724) 482-2163
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