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Gram Stain Kit

Item# KT-GRAMSTN

In Stock

$20.50 in_stock
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Quick Overview:
This kit allows you to differentiate bacteria using the Gram staining method.
Ages 13+

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Shipping Note: This item contains regulated chemicals and only ships Economy or Ground to a street address in the 50 US states.

More Information

Gram Stain Kit

Item# KT-GRAMSTN

This kit allows you to differentiate bacteria using the Gram staining method. It includes Hucker's crystal violet, safranin counterstain, Gram's iodine stain, ethyl alcohol, 12 plain microscope slides, 100 coverslips, a medicine dropper, non-latex gloves, and our own study guide.

Want to use this kit for a science fair project? See our experiment ideas below to get you started.

Test different types of bacteria, such as Gram-positive Bacillus cereus and Gram-negative Rhodospirillum rubrum and compare how the stains differ. (Or just order this bacteria culture comparison set.)

What is Gram staining? Hans Christian Gram, a Danish bacteriologist, discovered that bacteria could be divided into two different groups - one that retained a stain ("gram-positive") and one that didn't ("gram-negative"). His method for identifying these two groups became the first step in any bacterial identification process.

Gram's method of staining has several steps: a sample of bacteria is placed on a microscope slide, then is stained and "fixed" with iodine. The slide is then washed in a solvent to "decolorize" the first stain. Gram-positive cells will retain the stain even after being washed in the solvent, but the stain will be removed from the gram-negative cells. This is because the cell walls of gram-negative cells contain more lipids (fatty substances). The solvent dissolves the lipid layer, allowing the color to be drawn from the cell. The solvent causes the gram-positive cell wall to dehydrate, closing the pores and trapping the stain inside the cell. In the last step, the gram-negative cells are stained a different color, to contrast them from the gram-positive cells.

Science Fair Project Ideas:

  • Do antibacterial cleaners work more effectively against gram-positive or gram-negative bacteria?
  • Are common antibiotics equally effective against both gram-positive and gram-negative bacteria?



Take amazing close-up pictures of the bacteria you see under your microscope! This 3.0 Megapixel Digital Camera is a great deal! It takes high-clarity images and is easy to use.

Gram Stain Kit

  • Hucker's Crystal violet, 15ml
  • Ethyl alcohol, 30 ml
  • Gram's Iodine stain, 15ml
  • Gram Stain Kit instructions
  • Nitrile gloves, pair
  • Pipet (medicine dropper)
  • Safranin O stain, 15ml
  • Slide coverslips
  • Plain glass slides, 12/pk
Customer Reviews
Great Product Review by
This is a perfect stain kit for beginners..
Awesome Review by
Great deal!
Great kit Review by
This is a great little kit with well written directions. We were able to make perfect slides on the first try. One kit should easily stain 100+ slides. Thanks HST!
great kit Review by
This is a great kit. Very nicely packaged. Wonderful kit for homeschool science. I recommend a wash bottle instead of a pipet so you will have all of the water for the process in one dropper. This is great site and I highly recommend it for homeschoolers. I already have second order together
Fun! Review by
This is a great kit. We made several slides after swabbing multiple items in the house. Can't wait to see them under the microscope.
Gram Stain Kit Review by
This is a pretty good good kit but has 1 deficiency, the decolorizer. The decolorizer in this kit is 95% ethyl alcohol, which gives inconsistant results. Professional grade results can only be obtained with a 1:1 mixture of ethyl alcohol and acetone. You can make your own by mixing the ethyl alcohol in the kit with 100% acetone (professional grade nail polish remover), available in drug stores, Walmart, etc., in the cosmetics department. Use equal amounts of each. Do not use the acetone from a hardware store. [Home Science Tools adds: There are many Gram stain procedure variations. Our Gram Stain Kit is built around a procedure that is very commonly used for educational purposes, providing consistent results and ease of use. If you have a Gram stain procedure you wish to follow that uses acetone, it is also available at Home Science Tools.]
Gram stain kit Review by
I am a bio major and I do frequent staining at home. Since I purchased this Gram stain set from HST I have been able to identify quite a number of different bacterial species. My primary doctor was impressed with the accuracy and reliability of the kit when I would identify colonies better than he could! (not that he woiuld know much about culturing and staining). I am fully satisfied with HST and will always purchase any product/s that can be used at a professional level. Great job Home Science Tools!
I'll be back Review by
I discovered this site looking for alternative supplier for gram stain supplies. When I found this item here at HST which included slides and cover slips as well as the necessary chemicals I decided to chance it. The order was shipped quickly and everything arrived well packed and intact. I am very impressed with the overall quality and service from Home Science Tools and I am assembling a 2nd order now. I highly recommend this particular item and HST in general.
Great product! Review by
I bought this kit as part of a home-school biology course for my son, since he can't get Biology in school this year. We've been practicing with it, and the instructions are excellent! Very clear, and even explaining where mistakes may occur, so one can avoid them. Thanks for a great kit!
Wonderful product Review by
I am a microbiology student/lab tech at a major university. i just recieved this today so i could practice different staining techniques and do work at home and this kit works great. its the same chemicals i use at my school and hospital i work at. great buy and great price. a must have if you're an aspiring microbiologist.
Gram Stain Kit = Great Results and Product Review by
This product is excellent for a great price also. I was planning on buying the gram stain kit from another science company but they wanted me to pay $40 for it. This also had the microscope slides the glass covers and the medicine dropper next to all the chemicals. The kit I was planning on buying only had the chemicals. The directions were excellent and easy to understand also. My results came out to be great at the end thanks to this Gram Stain Kit.
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