<PAGE>

                                                                   EXHIBIT 4.3.1

                            AMENDED ESCROW AGREEMENT


     This Escrow Agreement is made this 13th day of January, 2003, by and
between Oregon Trail Ethanol Coalition, L.L.C., a Nebraska limited liability
company ("OTEC"), U.S. Bancorp Piper Jaffray, Inc. ("Underwriter") and Midwest
Bank N.A., a Nebraska chartered banking corporation, with an office located in
Deshler, Nebraska ("Escrow Agent").


                                    RECITALS:

     WHEREAS, OTEC was formed for the purpose of constructing and operating an
ethanol plant near Davenport, in Thayer County, Nebraska;

     WHEREAS, OTEC is, or will be, conducting a public offering of its
membership units and pursuant to the terms and conditions of its prospectus,
OTEC has committed to escrow the proceeds of the membership units sold to
investors;


     WHEREAS, OTEC has retained the services of Underwriter to assist with the
sale of the membership units on a best efforts basis.

     WHEREAS, OTEC and Underwriter have agreed to provide for the impoundment of
the proceeds to be received from the sale of the membership units.

     WHEREAS, OTEC and Underwriter wish to establish an escrow account with
Midwest Bank, N.A. to hold the proceeds of subscriptions for the membership
units for a minimum of 18,000 membership units and a maximum of 24,000
membership units, until written instructions from OTEC have been received;


     WHEREAS, Midwest Bank N.A. is willing to hold the escrow account and serve
as Escrow Agent, in accordance with the terms and conditions provided in this
Escrow Agreement.

     NOW, THEREFORE, the parties agree as follows:

     1.   Establishment of Escrow Account. OTEC shall open and maintain an
escrow account with Escrow Agent which shall be an interest bearing account, and
shall earn interest at the rate offered from time to time by Escrow Agent (the
"Escrow Account").

     2.   Escrow Account Authorizations. Only officers of the Escrow Agent shall
be entitled to withdraw funds from the Escrow Account as provided herein. OTEC
shall deliver to Escrow Agent for deposit in the Escrow Account all funds,
checks, bank money orders, etc., received by OTEC from the sale of membership
units. All checks, bank money orders, etc. shall be made payable to "Midwest
Bank N.A. as Escrow Agent for Oregon Trail Ethanol Coalition, L.L.C.". OTEC
shall deliver to Escrow Agent with each subscriber's funds, the subscriber's
name, address, amount of investment and date of deposit. Escrow Agent shall
maintain this information in its records for the purpose of returning to each
subscriber the subscriber's funds in the event that the minimum equity offering
of $18 million is not subscribed by March 1, 2003, subject to extension by
OTEC to up to April 30, 2003, the OTEC prospectus (the "Termination Date"). All
proceeds so deposited shall remain the property of the subscriber and shall not
be subject to any liens or charges by the Escrow Agent or judgments or
creditors' claims against OTEC unless and until released to OTEC as hereinafter
provided. The pro rata amount of interest to be allocated to each subscriber in
the event the funds are returned to the subscribers will be based on the date of
the deposit of the respective subscriber's funds into the Escrow Account by
OTEC.

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     3.   Investment of Deposited Funds. The Escrow Agent shall invest all funds
received and deposited in the Escrow Account in United States government or
government agency securities, or certificates of deposit issued by banks with a
net worth of at least $18,000,000. Any investment of deposited funds must be
made in recognition that offering proceeds must be able to be transmitted
promptly to OTEC or the subscribers if the stated conditions are met. The
following securities are not permissible as investments: (1) money market funds;
(2) corporate equity or debt securities; (3) repurchase agreements; (4) bankers
acceptances; (5) commercial paper; and (6) municipal securities.

     4.   Withdrawals from Escrow Account.

          (a)  Disbursement Of 10% Of Escrow Funds. If the Escrow Agent
receives, on or before the Termination Date, subscriptions in an aggregate
amount of not less than $18,000,000 and written acceptance of each subscriber's
subscription by OTEC, and OTEC has met the Release Conditions set forth in
Paragraph 4(c) below, then the Escrow Agent shall disburse, upon written
instruction from OTEC, substantially in the form attached hereto as Exhibit A,
10% of the subscription payments held in the Escrow Account to OTEC ("Initial
Disbursement"). If the Escrow Agent receives additional subscription payments
after the Initial Disbursement, the Escrow Agent shall deposit the subscription
payments into the Escrow Account and upon receiving written instruction from
OTEC, substantially in the form attached hereto as Exhibit A, shall disburse to
OTEC 10% of all subscription payments received after the Initial Disbursement.
The Escrow Agent shall retain the remaining 90% of all subscription payments in
the Escrow Account to be disbursed as set forth in Section 4(b) below.

          (b)  Disbursement Of Remaining 90% Of Subscription Payments. Upon
receipt by the Escrow Agent of written confirmation from OTEC that OTEC has
received an executed commitment letter from a lender for the amount of debt
financing that OTEC determines necessary ("Commitment Letter Notice"), and OTEC
has met the Release Conditions set forth in Paragraph 4(c) below, the Escrow
Agent shall disburse to OTEC, pursuant to written instruction from OTEC,
substantially in the form attached hereto as Exhibit A, the remaining 90% of the
subscription payments remaining in the Escrow Account in immediately available
funds ("90% Disbursement"). If the Escrow Agent receives additional subscription
payments after the 90% Disbursement, then the Escrow Agent shall disburse the
subscription payments to OTEC upon written instruction from OTEC, substantially
in the form attached hereto as Exhibit A. If the Escrow Agent does not receive
the Commitment Letter Notice from OTEC by the Termination Date, then the Escrow
Agent shall refund to subscribers with interest determined on a pro rata basis
per subscriber, the remaining 90% of each Subscriber's subscription payment per
written instruction from OTEC.

          (c)  Conditions on Disbursements. OTEC shall not withdrawal funds from
the Escrow Account under Paragraph 4(a) or Paragraph 4(b) above for use by OTEC
unless the following conditions are met (the "Release Conditions"): (a) there
shall not be any legal orders prohibiting the offering or release of funds from
escrow, or orders from the United States Securities and Exchange Commission
revoking the effectiveness of the Registration Statement related to the
offering, and (b) the Escrow Agent has contacted the Securities Bureau of the
Nebraska Department of Banking and Finance (the "Bureau") and the Bureau has
indicated that the funds may be released from the Escrow Account.

     5.   Termination of Escrow Account. In the event that OTEC has not received
subscriptions for the minimum offering amount by the Termination Date, then OTEC
shall instruct the Escrow Agent to return to the subscribers, all funds from the
sale of membership units held in the Escrow Account with interest determined on
a pro rata basis per subscriber.

                                        2

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OTEC may, in its sole discretion, abandon the sale of the membership units at
any time prior to the termination of the offering period. Upon the receipt of
written instructions from the Chairman of the Board or President of OTEC that
the offering is being abandoned, the Escrow Agent shall refund the monies on
deposit to the subscribers thereof as provided in this Paragraph 5.

     6.   Escrow Agent's Reliance. Escrow Agent shall be under no duty or
responsibility to make any inquiry or investigation as to the accuracy,
adequacy, and shall be entitled to assume conclusively, correctness and
completeness of any and all information given in any affidavit, statement, or
other paper received by Escrow Agent under this Escrow Agreement, including, but
not limited to the prospectus. Escrow Agent shall be entitled to rely upon any
notice, request, affidavit, approval, statement, consent or other paper believed
by Escrow Agent to be genuine and to have been signed by the proper party or
parties.

     7.   Hold Harmless. Escrow Agent shall not be liable to OTEC and/or any
subscriber for any error of judgment, or for any act done or step taken or
omitted by it in good faith, or for any mistake of fact or law, or for anything
which it may do or refrain from doing in connection herewith, excepting only its
own intentional and deliberate misconduct.

     8.   Indemnification. OTEC agrees to defend, indemnify and hold Escrow
Agent harmless from and against any and all claims, actions, judgments, losses,
liabilities, obligations, damages, charges, costs, and expenses of any nature
whatsoever, including, without limitation, reasonable attorneys' fees and
expenses incurred by Escrow Agent (including such fees and expenses incurred in
any litigation by or against any of the parties to this Escrow Agreement under
this Paragraph 8, arising directly or indirectly from, out of or incident to
this Escrow Agreement, excepting only those accruing as a result of Escrow
Agent's own intentional and deliberate misconduct).

     9.   Escrow Agent's Fees. Escrow Agent shall be entitled to charge OTEC a
fee for providing services hereunder in accordance with the terms of Exhibit B
attached hereto and incorporated herein by reference.

     10.  Time. Time is of the essence of this Agreement.

     11.  Applicable Law. The interpretation and enforcement of this Agreement
shall be governed by the laws of the State of Nebraska.

     12.  Binding Effect. This Agreement shall be binding upon the parties and
their respective successors and assigns.

     IN WITNESS WHEREOF, the parties have hereunto signed this Agreement.

OREGON TRAIL ETHANOL COALITION, L.L.C.       MIDWEST BANK, N.A.,
a Nebraska limited liability company         a Nebraska chartered banking
                                             corporation


By:      /s/ Mark Jagels                     By:      /s/ Rob Schardt
   -----------------------------------          --------------------------------

   Its:  Chairman of the Board                  Its:  President
       -------------------------------              ----------------------------


U.S. BANCORP PIPER JAFFRAY, INC.

By:      /s/ Mark E. Fisler
   -----------------------------------
   Its:  Managing Director
       -------------------------------


                                        3

<PAGE>

                                    EXHIBIT A

                         FUND DISBURSEMENT INSTRUCTIONS


The undersigned certifies that he, she or it is duly authorized to execute and
deliver this Escrow Notice on behalf of Oregon Trail Ethanol Coalition, L.L.C.
("OTEC"). Pursuant to the Amended Escrow Agreement dated January 13, 2003 (the
"Escrow Agreement") by and among OTEC U.S. Bancorp Piper Jaffray, Inc.
("Underwriter") and Midwest Bank, N.A. (the "Escrow Agent"), OTEC hereby request
that the Escrow Agent remit, in immediately available funds, $_____________ from
the Escrow Account to the following parties as follows:


                  PARTY                          AMOUNT
                  -----                          ------

                                                 $


                                     TOTAL       $


IN WITNESS WHEREOF, the undersigned have executed this Fund Disbursement
Instruction as of the date set forth below.


OREGON TRAIL ETHANOL COALITION, L.L.C.
a Nebraska limited liability company


By:
   --------------------------------------------------

   Its:   Chairman of the Board
       ----------------------------------

                                        4

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                                    EXHIBIT B

                                  FEE AGREEMENT

     Regardless of whether the Release Conditions are met by the Termination
Date the Escrow Agent shall be paid a fee of $500 plus the aggregate of the
Daily Escrow Charges (as defined below) for each day funds are held in the
Escrow Account . The "Daily Escrow Charge" shall equal the balance of the funds
held in the Escrow Account on each day multiplied by .005 and then divided by
365.