Making E-Broth

This will be a simple medium which you can make from ground beef and you can add cornsyrup and other items to it if you wish. I am making up a batch of this and you can follow along if you wish. It is based on the classic broth that has been used for a century, but is not quite the same. That broth will be made later. The idea here is for you to experiment with adding or leaving out some materials that you do not have. [You don't have peptone. We will talk about peptone later.

Making E-broth.

I called this Easy Broth, but it does take two hours to make, plus another couple hours to finish all the other variations. I will give the measurements in cups and spoons to get you started easily.

I weighed out 4 oz of ground lean beef, but hamburger will do fine. Rolled into a sphere, this was a ball 2.25 inches in diameter, exactly the inside diameter of the mouth of a mason canning jar. If you don't know what a mason jar is ask anyone who cans vegetables. The quart size of Kraft salad dressing is an example.

I slid the ball of meat into the jar and added 2 cups of tapwater, cold or warm, and began stirring to extract as much of the sugar, proteins, blood, amino acids. I let it stand one hour, longer is better, with occassional stirring.

I poured it into a pan and put it on the kitchen stove using high heat to bring it to a boil. Then I let it simmer for 1/2 hour. The purpose of this is to coagulate proteins so we can filter them out. Observe this coagulation. Notice that the meat turns pale brown and the blood is coagulated. Avoid excessive evaporation because we want as much liquid as possible. Stir most of the time so it does not burn.

When the 30 minutes is up (length of time is not important), filter it through a handerchief or similar tightly woven clean fabric. We want the filtrate to be as clear as possible, but the bacteria don't care. lay the hankerchief over the measuring cup and push the center down into the cup and pour the mixture onto the handkerchief. Pick the cloth up by the corners and let the juice drain into the measuring cup. If you wish gently twist to speed the process, but be careful as twisting pressure can cause particles to come through with the liquid.

I got 1 cup of broth. I looks kinda thin so I did not add more tapwater to bring it to the original volume of 2 cups as I usually do. I set the broth in the refrigerator so the fat floating on top can solidify and and the pieces easily removed tomorrow. I used the left over meat for cooking human dinner. Actually, the meat makes good food for many bacteria. Sometimes, I do not filter, I just use the whole mixture, but I always but it in the refrigerator overnight to let the fat solidify. It will not rot overnight because we have pasteurized it by this cooking--ask any cook. You can let it sit until you get home from school tomorrow. Notice that we worked cleanly. We avoided introducing needless spores and bacteria, especially after we finished the cooking.

Goodnight, see you tomorrow. We will put it in containers and sterilize it.

Some of the stuff below will guide us for the E-broth.

Preparation of the Medium.

Medium is the name we give to the food we grow our microbes in. Medium must contain everything our yeast needs.

Tube your medium and sterilize your medium.

Items below this line are to help me in writing this page This was original meat media page; placed here for depleting on Feb 4

Making Bacteria Media from Meat

Using common foods for Microbiological Media

By Harold Eddleman, Ph. D.

We call the food for our microbes medium (plural = media). In the early days, only kitchen foods were available for microbiological media. While such media are now less common in professional labs, the amateur scientist and schools can make good use of them. Look around your home and think about ways you can use the foods at hand.

Meat Based Media

Media derived from meat and its products are very common in medical laboratories because much of our knowledge of medically important microbes is based on the meat media. Actually most organisms grow better on media made from milk, but milk is white and it is more difficult to see the growth of microbes in milk.

If ground meat is soaked in water, the soluble proteins are extracted. When meats are cooked or roasted in canning factories, the juices are often sold in various forms for flavorings. Such meat extract was used by the early microbiologists for convenience. Nutrient broth and nutrient agar made from such products is the most widely known media to teachers and students. However, media based on tryptone are more complete and support the growth of more species of bacteria.

General Comments


You will often see the word Broth as you read the literature of bacteriology. You may have heard of Nutrient Broth and Nutrient Agar. They are very similar to classic Broth, but bacteria grow better on the genuine Broth you prepare at home from fresh ground beef. Classic Broth is mainly used for growing organisms from intestine or decaying meat.

  1. Mix 1 volume of fresh ground beef with 1 volume of tapwater and let stand overnight in refrigerator or room temperature.
  2. Heat to boiling, with stirring, to coagulate proteins.
  3. Filter through cloth. Discard the meat. If you worked cleanly and used refrigerator temperature for the extraction, the discarded meat is safe for human food.
  4. Add 1% peptone and 0.5% table salt (sodium chloride).
  5. Adjust pH to neutral using dilute NaOH (1.0 Normal is suggested)
  6. Heat to boiling again and filter thru filter paper if perfectly clear Broth is wanted.
  7. Dispense into tubes, plug with cotton, and autoclave.

That is the way professionals have made broth for a century. Such broth was used mainly for growing bacteria from human feces. Ground veal was sometimes used as some species grow better on the richer veal broth.

E Broth

Eddleman Broth is simpler for your home micro lab and many bacteria will grow very well on it, but the scum, sediment, and other results of bacterial growth will differ somewhat from the results on classic broth. Some bacteria grow better if you omit the salt. Salt (5 grams per liter) is used added if we are growing bacteria from human gut or decaying meat, but the bacteria usually grow fine without the salt. We will omit peptone because you don't have it. Use ground beef, or ground liver, or any kind of meat you wish.

  1. Mix 1/2 pound of fresh ground meat with 1 liter of tapwater and let stand several hours in the refrigerator, stir occasionaly to aid extraction of soluble proteins.
  2. Heat to boiling, with stirring, until the meat is cooked to coagulate proteins.
  3. Filter through a white cloth which is thick enough to remove all particles. Discard the meat. If you worked cleanly (clean pans and clean cloth) and used refrigerator temperature for the extraction, the discarded meat is safe for human food.
  4. Chill the broth in refrigerator so that the fat forms a hard floating layer. Discard the fat.
  5. Adjust the volume to one liter by adding tapwater.
  6. Do not adjust pH because you do not have a pH meter or pH paper and most bacteria will grow fine. If you wish add a 1/8 inch crushed limestone pebble to some of the culture tubes to see if there is any difference in growth of bacteria, or use powdered limestone or calcium carbonate.
  7. Dispense into tubes, plug with cotton, and autoclave in pressure cooker at 15 pounds pressure for 15 minutes. Let tubes cool in pressure cooker.

E broth will not give the same results as classic broth, but commercial nutrient broth will not give the same results either. Do not worry that you are making an inferior medium. E broth is what I often use. You need not remove the meat. The meat particles will buffer the medium and some bacteria will grow better, especially proteolytic Clostridium species. See LP liver particles medium.

Some Kitchen Foods Useful for Microbiology

Gelatin or Jello - can be used in tubes or plates to solidify medium or to test gelatin liqufaction

Potato Slices - Potato slices can be used as solid medium for streaking and isolating bacteria which are capable of growing on them.

PDA - Potato Dextrose Agar - is the best medium for growing many fungi, and bacteria and some yeasts. cook potato in P cooker, filter thru cloth. add corn syrup to make a lliquid medim. Add agar for solid medium

A word about agar. Agar is a gel from seaweed.. 10 to 15 grams is enough to sollidify agar. Use 7 gram per liter for soft agar. Agar comes from seaweeds and the gelling temp varries form 27C to 49C and Bact grade gells at 37C.

Carrot puree or carrot water is good for phytobacteria dnd fungi.

Starch will serve as carbon and energy source for many fungi and bacteria.

Sucrose is a c and E dource for fungi, and the bacteria able to hydrolyze it.

Red Cabbage juice is a pH indicator red in acid. I do not rememer the point where it changes.

Bacteria and fungi require a nitrogen source.

  • B023 - Making media (food) for your microbes from common kitchen foods
  • Vinegar or battery acid or Muricatic acid can lower pH of medium.

    Sodium carbnate or bicarbonate can raise pH

    DUST falls

    If you remember that dust falls or is blown by wind, you will have fewer contamination problems. Thus a loose foil cover or lid will protect a container from contamination. .

    Some items to sterilize and have on hand

    Safety Now. Don't begin this experiment until you have read my general safety page and the special safety notes for these experiments at the bottom of this page. Become a student who always works carefully and safely.

    Tube your medium and sterilize it.

    Record the results

    Suggested Further Experiments

    Most advanced microbial experiments require the use of solid media for isolation of pure cultures and the use of sterile medium. Pasteur accomplished much using selective methods, but he and others began using sterile medium and then rapid advances began.

    move page LINK for moremedia and steiliar;ona

    sterile toothpicks tostart rotten apples

    tyddalize milk 3 days in a row save a conrtol

    Safety Rules for Microbiology

    Safety First. Do not sniff moldy items. There is a chance that the spores could get into your longs and begin to grow. Certain fungi can grow in our lungs and antibiotics do not help much. Death has a good chance of occuring if you get infected by such fungi. I will write about the fungi later. Actually, one cubic centimeter of air in homes commonly has 5,000 or 8,000 particles of dust and some of these are mold spores including the dangerous ones. Each good deep breath contains about 20 million particles.

    Rule #1. Don't waste too much time wishing for equipment you don't have. Spend your time thinking about things you can do with what you have.

    I love working with bacteria, yeasts, fungi, protozoa, algae, and bacterial viruses at home. The study of these things is called microbiology. The study of all of them uses approximately the same equipment. Therefore, this series of pages B020 => B024 will concentrate on the supplies and equipment for studying bacteria. Later, I will write pages about the equipment to study the other organisms.

    You should read these pages in the order listed.

  • I might be helpful to read the first four pages before you do anything. The begin some simple experiments and you will learn what you need. Later you may want to buy some supplies, but at first see how much you can do with items from your home, farm, and gifts of discarded items.

  • First installed January 1998      Revision #2 1998 Feb 3
    Written by Harold Eddleman, Ph. D., President, Indiana Biolab, 14045 Huff St., Palmyra IN 47164
    | Indiana Biolab | Home Micro Lab | Bacteria Evironmental Needs | Food Microbiology |

    Begun 1998 Feb 3      Revision #1 1998 Feb 3

    Written by Harold Eddleman, Ph. D., President, Indiana Biolab, 14045 Huff St., Palmyra IN 47164
    Please help by sending me an e-message containing your ideas for improvement.

  • If you have a pressure cooker, you can use it to kill all the microbes, including spores of all kinds and viruses.
  • If you have a pressure cooker, put your liquid medium in a glass jar with the lid on loosely and cook (autoclave) at 15 pounds pressure for 15 minutes. Read the manual for the pressure cooker to learn the setting for 15 pounds and read the safety precautions. Get the owner of the cooker to supervise your work. It is possible for a pressure cooker lid to fly off and injure you. Do not forget to p

    In fact, the early humans and all animals and plants are involved with microbes. With each breath, you inhale about 5 million to 20 million dust particles and many of those are microbes.

    Bacteria and other microbes are all around us. I am having trouble getting this page started because there are so many things we can do that I do not know what will interest you the most. I will just begin listing some simple experiments and you can do what ever you like.