Practical 

Procedures For 

Sampling Grain

At Farm Sites

And Remote 

Locations

Marketing and

Regulatory

Programs

Agricultural

Marketing

Service

Federal Grain

Inspection

Service

Washington, D.C.

September 2016
Practical Procedures for Sampling Grain 

at Farm Sites and Remote Locations

March 30, 2015

Page 2

Practical Procedures For Sampling Grain

At Farm Sites And Remote Locations

The Importance Of Sampling

Sampling is an essential part of the inspection process and is critical to the 

accuracy of the final grade. If the sample is not representative of the lot, the 

inspection result will not reflect the true quality of the lot.

Basic Principles of Obtaining a GOOD sample:

• Collect several samples from different areas of the lot.

• Combine these samples to form a single sample.

• Consider the size of the sample needed for analysis.

• Completely mix or blend the final sample.

Tailgate Sampling

Use a container (a large coffee can will work) to sample grain from a moving 

stream of grain. Tailgate sampling will draw a reasonably representative 

sample as grain is loaded/unloaded from a combine to a truck/wagon or from a 

truck/wagon to a bin.
Practical Procedures for Sampling Grain 

at Farm Sites and Remote Locations

March 30, 2015

Page 3

To Obtain A GOOD Sample With A Tailgate Sampler

• Let the grain flow from the carrier (truck, combine, bin) for a few seconds 

before taking your first sample. Avoid sampling the last few bushels 

flowing out of the container.

• Hold the sampling device so that it is at one side of the grain stream.

• Pull the tailgate sampler through the grain stream in a continuous motion.

• Empty each sample into a clean, dry container.

• Take a minimum of three samples per carrier. More samples will yield a 

more representative composite sample.
Practical Procedures for Sampling Grain 

at Farm Sites and Remote Locations

March 30, 2015

Page 4

Probe Sampling

A hand probe is the only effective method of obtaining a representative sample 

from grain at rest in a truck bin or other container. There are two types of hand 

probes - a compartmented probe and an open-throat probe. 

The open-throat probe does not have compartments inside. This feature 

allows the sample to be poured directly from the probe into a sample 

container. The open-throat probe tends to draw more grain from the top 

portion of the lot. Results of the open-throat probe will differ from that of a 

sample drawn with a compartmented probe. 

Hand probes come in 5’, 6,’ 8’, 10’, and 12’ lengths. The sample is more 

representative of the lot if the probe reaches the bottom of the carrier.
Practical Procedures for Sampling Grain 

at Farm Sites and Remote Locations

March 30, 2015

Page 5

To Obtain A GOOD Sample With A Hand Probe

• Determine the locations in the container to be probed. Avoid sampling in 

the spout stream.

Flat Bottom Truck - 5’ or 6’ probe

X

X X

X

X

Hopper Truck - 6’ to 10’ probe

X X

• With the slots on the probe closed, insert the probe at a slight angle (10 

degrees).

• With the slots facing upward, open the probe and move it up and down in 

two short motions to fill the compartments.
Practical Procedures for Sampling Grain 

at Farm Sites and Remote Locations

March 30, 2015

Page 6

• Close the probe, withdraw it from 

the grain and empty the grain 

onto a canvass or trough that 

is slightly longer than the probe 

you are using. If you are using 

an open-throat probe, pour the 

grain from the open end of the 

probe directly into a clean, dry 

container.

• While drawing the sample, 

observe the general condition 

of the grain and check for 

objectionable odors, insect 

infestation, large stones, pieces 

of metal or glass and any other 

potentially harmful conditions.
Practical Procedures for Sampling Grain 

at Farm Sites and Remote Locations

March 30, 2015

Page 7

Getting The Sample Inspected

A grain inspector will need about 2 to 3 pounds of grain for a complete grade. 

Additional grain may be needed if other criteria factors such as aflatoxin, 

vomitoxin, protein, falling numbers, are requested.

Submit your sample to an “Official Grain Inspection Agency” to ensure 

you receive accurate, timely inspection results on your sample. Official 

grain inspection agencies are authorized by USDA, GIPSA, Federal Grain 

Inspection Service, to inspect and certify the quality of grain. These agencies 

use only equipment that is approved and tested by the Federal Grain 

Inspection Service. Official grain inspection agency employees are

licensed and monitored by the Federal Grain Inspection Service.

Click here to locate the “Official Grain Inspection Agency” in your area.

The Bottom Line

By drawing a representative sample and getting an accurate inspection, you 

will know the true quality of the grain at the time of sampling. The condition of 

stored grain can change depending on the conditions of the storage area and 

the quality factors of the stored grain.