Air Cooling™:

What is Air Cooling™?

The Air Cooling™ models have devices which exchange air with their surroundings; they do not have refrigeration units. Air Cooling™ effectively draws cold air into the instrument if you are using the Bullet Blender ® in a cold room or a refrigerated cabinet. Air Cooling™ is also useful if you’re running several sample cycles in a row or if your samples are extra sensitive to heating up. Normally, the samples in the Bullet Blender ® only heat up a few degrees and stay quite cool. However, if you’re running a second batch of samples soon afterward, they will heat up a little more because the Bullet Blender ® is starting out slightly warmer. The Air Cooling™ keeps the Bullet Blender ® cooler so that the first batch of samples heat up a little less and subsequent batches are kept just about as cool as the first batch.

Which models have Air Cooling™?

The Air Cooling™ feature comes on the “Blue” models: the Bullet Blender ® Blue which uses microcentrifuge tubes, the Bullet Blender ® Blue 5 which uses 5 mL tubes and the Bullet Blender ® Blue 50 which uses 50 mL tubes.  Air Cooling™ is also included with the Bullet Blender ® Storm.


Use and Operation:

How is the Bullet Blender different from other high-throughput homogenizers on the market?

The Bullet Blender is similar to other Bead Mill Style homogenizers in that it processes each sample in its own tube using homogenization beads. Therefore, there is no chance of cross-contamination and there are no parts that need cleaning after each sample. A unique feature of the Bullet Blender is the way it agitates the sample tubes. Other homogenizers vigorously shake the sample tubes. This requires a great deal of energy and these instruments tend to be very large (because of the motor), expensive (many are 2 -3 times the cost of the Bullet Blender) and require cooling cycles due to motor heating – this can take a lot of time away from experiments. The Bullet Blender, on the other hand, uses a patented striking method to agitate tubes. This requires a much smaller motor and generates much less heat. Therefore the Bullet Blender is smaller, lighter, and less expensive than competitor’s equipment while working just as well. The Bullet Blender can also be used in a cold room unlike many of the other instruments on the market.

What types of tubes can be used?

The Bullet Blender ® Storm works with 1.5ml Eppendorf® Safe-Lock tubes. The Bullet Blender ® and Bullet Blender ® Blue work with 1.5 mL, 1.7 mL, and 2.0 mL polypropylene sample tubes, including conical and round bottom microcentrifuge snap-cap tubes. We recommend Eppendorf® Safe-Lock tubes.  When using 2ml tubes in the the Bullet Blender® or the Bullet Blender® Blue we recommend using a minimum of 2 tubes per homogenization cycle.  The screw cap models use Axygen® and Corning® 1.5 ml screw cap tubes. The Bullet Blender ® Blue 5 units work with 5ml Axygen® brand screw top transport tubes. The Bullet Blender 50-DX units work with 50 mL skirted (self-standing) polypropylene tubes, such as Axygen® brand or Corning® brand. The slightly hazy polypropylene tubes are tougher and resist the striking better than the clearer tubes, which might crack at higher speeds. Use high quality tubes, rather than bargain brand tubes which are not as strong.

How do you set the Bullet Blender ® to mix, disrupt, or homogenize different types of samples?

You can adjust the speed and the duration. Adjusting the speed affects how firmly the balls will strike the sample tubes, while adjusting the duration affects the total number of impacts. Homogenizing tough tissue requires longer durations at full speed, while mixing requires lower speeds.

How easy is it to operate the Bullet Blender ®?

Simply place up to 24 sample tubes in the holders, set the desired duration and speed, and push start. All the samples will be processed simultaneously, without any chance of cross contamination.

How much volume of sample can be homogenized in each microcentrifuge tube?

For the BBX24 model Bullet Blenders, we recommend using 10-300mg of tissue in a standard microcentrifuge tube. Less than 10mg will work, but it requires careful attention to the amount of beads and volume of homogenization buffer. As with any experiment, errors become larger as the measured quantity gets smaller, so reproducibility becomes an issue. Samples larger than 300mg are not recommended. The air volume inside the tube is critical to allow the sample to be ground up inside the tube, so if the tube is more than 75% full, the efficiency of the homogenization is reduced. The 5 mL tubes can hold up to about 1 g of sample tissue or cultured cells, and a total of 3.5 mL of sample, buffer, and beads combined. The 50 mL tubes can hold up to about 3.5 g of sample tissue or cultured cells, and a total of 20 mL of sample, buffer, and beads combined.

Do sample tubes need to be placed symmetrically?

No. There are no restrictions as to which holes to place your sample tubes in, however you may get better results if you space them apart as evenly as possible.

How do you retrieve the sample from the tubes?

After the Bullet Blender® stops, centrifuge the tubes to clarify the lysate prior to use in your molecular biology applications.

Which beads should I use?

The protocols page contains suggested beads, speeds, and durations for processing many types of tissues and cells. The Bullet Blender ® beads page has a bead selection table. The two basic rules for bead selection: (1) use denser beads for tougher samples, and (2) use beads of a comparable size to the size of your samples to maximize the effectiveness of collisions between beads and samples. For example, if you wanted to lyse bacterial cells with a soft membrane, use small glass beads. If you want to homogenize larger pieces of tough tissue, use large steel beads.

I am trying to process tough samples in the Bullet Blender ® and the homogenization is incomplete. How can I improve my results?

There are several ways that you can increase the homogenization of your samples.

Bullet Blender Homogenization Aspect Ratio
– Examine the shape of your samples- long thin samples will homogenize faster than cube-shaped or round samples.
– Try cutting your samples into smaller pieces.
– If you are running many samples at once in the Bullet Blender, try runing fewer tubes at a time. If a sample is extremely tough (e.g. mouse femur) you may only be able to achieve complete homogenization with 2-4 tubes at a time.
– If you are using the BB50-DX make sure that all of the sleeves are removed except for the sleeves containing tubes.


I previously owned another bead mill homogenizer. Can I use the same protocols that we developed for the other homogenizer with the Bullet Blender ®?

No, the mechanism of action is different from all other homogenizers on the market. Our patented striking technology makes the Bullet Blender both highly efficient and effective. If you use another product’s protocol with the Bullet Blender, you are very likely to experience different results. Please use one of our established protocols, or empirically determine a protocol that works best for your samples.

We would like to use Fisherbrand tubes with the Bullet Blender®. Do they perform well?

Due to difference in shape, Fisherbrand tubes are more susceptible to wear in the Bullet Blender. We therefore recommend that you avoid using Fisherbrand tubes with the Bullet Blender. If you must use Fisherbrand tubes, do notuse them in runs of more than four minutes.

Why is there a three tube minimum for Bullet Blender ® 5 and a two tube minimum for the Bullet Blender ® 50-DX?

These Bullet Blender models contain larger motors. If all the energy were directed at a single tube, the tube might break. Tubes partly filled with water can be used in place of a tube filled with sample.

Is it possible to homogenize tissue that has been frozen in liquid nitrogen?

It is possible to homogenize tissue that was frozen in liquid nitrogen. Immerse the frozen tissue in cold buffer and allow it to thaw, then treat it as you would any other sample. If the tissue was dried before it was frozen, you can pulverize the tissue by running the tissue with beads only (no buffer), then adding the cold buffer and running again to complete the homogenization. You cannot homogenize “wet” tissue while it is still frozen, as it will effectively be a block of ice and homogenization efficiency will be very poor.

What is the “Key-Switch Lock Out” option for Bullet Blenders?

This key switch option incapacitates the electronics, preventing others from operating your Bullet Blender. Thereby, others are discouraged from working in your area, using your supplies, and upsetting your experiments.