In all cases of trying to determine if a product is yoshon or not, one compares the date found on their product to the Date Code mentioned on our site. If the date on your package is earlier than the Date Code on Yoshon.com, it is yoshon.

What if it is early in the season, and your product isn’t updated on Yoshon.com yet? What do you do then?

One can often calculate date codes on their own through simple calculations. The main thing one needs to know is when a product was made. This ultimately determines whether a product is yoshon or not.

Every year, the general chodosh cutoff dates for each of the different grains are released. These are packing dates, and it changes every single year. Any date before these listed dates are yoshon. If it is the listed date or after, an item may be chodosh.
For example, If an oat item was made on July 8, 2020, and the chodosh cutoff date for oats that year was July 24, 2020, it is yoshon. If an oat item was made July 25, 2020, it would be chodosh.

There are two tools needed- the general chodosh cutoff date as mentioned above, and the “Shelf Life” of a product. Often, products on our site will have a Shelf Life listed. It will appear under the “Additional Information” tab within a product listing on our site.

A whole page of tools can all be accessed together on our Tools page.

One can also contact a company to find out when it was made. Be sure to ask “What is the exact amount of time between the Manufacturing Date and the Best By Date?”

Note: Never ask, “What is the Shelf Life?“, because the agent will most likely think that you mean how long will the product stay fresh after it is opened. You will usually end up getting the wrong answer.

Tools for Date Calculations
Here are links to these tools.

The General Chodosh Cutoff Date Sheet
This has the list of all of the different grains and their cutoff dates. If your product has multiple grains, always use the earliest occurring date.

Date Calculator Tool
This excellent tool works on addition or subtraction. Type in your date in the “Start Date”, choose “Add” or “Subtract” from the menu, and enter the desired Shelf Life time into either “Years”, “Months”, “Weeks” or “Days”. Click on “Calculate New Date”, and it will give you the answer.

Calculate It!
With the shelf life, a best by date can be calculated from the chodosh cutoff date. It also works the other way around, the packing or manufacturing date can be derived from a Best By Date. Let’s see how this is done.

To Calculate a Packing Date from a Best By Date
The packing date or “Manufacturing Date”, is the key to knowing if a product is yoshon or chodosh. If an oat item had a Best By date of July 28, 2021, and the shelf life was one year, one merely subtracts one year from Best By Date to get the actual packing date of July 28, 2020.
Compare this date with the Chodosh Cutoff Date for oats of July 24, 2020, and it means it is chodosh.

Now, let’s say that the same product from a different company had a shelf life of 18 months, but the same Best By date. Subtract 18 months from July 28, 2021, and it would be January 24, 2020. Since the Cutoff Date for oats is July 24, 2020, and January 28, 2020 is before that date, it is yoshon!

Here it is in a more visual example:
Best By Date – (Minus) Shelf Life = (Equals) Manufacturing Date

The opposite works as well…

To Calculate the Best By Date from a Packing Date
This is what we do on Yoshon.com. This can come in handy early in the season if a product hasn’t bee updated yet. As long as we have the Shelf Life listed in “Additional Information”, it can be figured out. Take the Packing date and add the Shelf Life time to it. This will give you the Best By Date.

Say you have a box of Saltine Crackers. Its Shelf Life is 6 months, but it isn’t updated on Yoshon.com yet this year.
The Chodosh Cutoff Date for Wheat is August 6, 2020. Add 6 months to August 6, 2020, and you get February 6, 2021.

Compare this Best By Date with the Best By Date on your package of Crackers. If it is before that date, it is yoshon. If that date or after, it is chodosh.

Here it is in a more visual example:
Packing Date + (Plus) Shelf Life = (Equals) Best By Date

Calculating Julian Dates
Another type of code is called the “Julian Date”. It is merely a 3-digit numbered day of the year. January 1st would be 001, and on a regular year December 31st would be 365, or in a Leap year 366. We have a Julian Date Cheat Sheet for each type of year in our Updates and Downloads page.

Julian Dates Cheat Sheet for a Regular Year

Julian Dates Cheat Sheet for a Leap Year

Once merely needs to translate the Julian date into a Gregorian date to do the calculations.

Lot Codes
Lot codes are usually packing dates, which consists of a series of numbers made up of the year and the Julian date. The Julian-based Lot Code is most often 4 or 5 digits, with the year being either first or last. Sometimes it starts with one or two letters designating a certain plant location or shift, which is unimportant and can usually be ignored. (Less often, it may be within a longer code, but in this case, they are often the first digits of the code.)
The important thing to remember is to first isolate the year, then look up the Julian date to translate it into a Gregorian date.

As a 4-digit code for December 31, 2019, it can be listed as 9365 (YDDD) or 3659 (DDDY).
As a 5-digit code, the same date may be listed as 19365 (YYDDD) or 36519 (DDDYY).

It is only slightly harder when the year is the start of a new decade, but generally the lot code’s year is going to be fairly current, either last year or the current year. A lot code will never be in the future.

As a 4-digit code for February 1, 2020, it can be listed as 0032 (YDDD) or 0320 (DDDY).
As a 5-digit code, the same date can be listed as 20032 (YYDDD) or 03220 (DDDYY).

One needs only to translate the Julian Code into a Gregorian date, then compare it to the Chodosh Cutoff Date for the earliest grain in the product. The beauty of Packing Dates is there are no further calculations needed- no addition or subtraction. They are by far the most accurate method of seeing if your product is yoshon or chodosh.

An excellent calculator can be found on the Julian Date Converter Tool, where they use a 8-digit code, with the four numbers of the year coming first (YYYY-DDD). Comparing to the above, it would be written as 2020-032 (February 1, 2020 or YYYY=2020, 032=February 1).

We hope this helps everyone. Happy calculating!

The TYNI Staff

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If you need to learn about date codes and keeping yoshon in general, this is a great book for newcomers. It makes a great gift for family members who want to learn as well.

Updated As Of:
January 22, 2024