ETHANOL MARKETING AGREEMENT

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                                                                    EXHIBIT 10.1

                           ETHANOL MARKETING AGREEMENT

This Ethanol Marketing Agreement ("Agreement") is made and entered into as of
the 14th day of October 2002 by and between VeraSun Energy Corporation, a South
Dakota corporation ("VERASUN") and Williams Ethanol Services, Inc., a Delaware
Corporation DBA Williams Bio-Energy ("WES").

In consideration of the mutual terms and conditions contained herein, the
Parties agree as follows:

1.   Terms and Termination

     A.   The term of this Agreement shall commence on the first day of ethanol
          sales and continue for a primary term of two (2) years and thereafter,
          renewing for consecutive two (2) year terms, unless terminated by
          either party with at least six (6) months prior written notice without
          cause.

     B.   In addition, this Agreement may be terminated under the circumstances
          set out below.

          (1)  Termination for Intentional Misconduct. If either party engages
               in intentional misconduct reasonably likely to result in
               significant adverse consequences to the other party, the party
               harmed or likely to be harmed by the intentional misconduct may
               terminate this Agreement immediately, upon written notice to the
               party engaging in the intentional misconduct.

          (2)  Termination for Uncured Breach. If one of the parties breaches
               the terms of this Agreement, the other party may give the
               breaching party a notice in writing which specifically sets out
               the nature and extent of the breach, and the steps that must be
               taken to cure the breach. After receiving the written notice, the
               breaching party will then have thirty (30) days to cure the
               breach, if the breach does not involve a failure to make any
               payments which are required by this Agreement.

               If breach involves lack of payment beyond the established
               delinquency period, as specified in this Agreement, VERASUN may
               terminate this Agreement immediately and without prior written
               notice.

          (3)  Change of Control. Based on a change of majority interest in WES,
               VERASUN shall have six (6) months to terminate this agreement
               following the receipt of written notice regarding such change of
               ownership. WES must notify VERASUN of said event in writing
               within two (2) weeks of event. VERASUN may terminate agreement
               with (30) days written notice within said six (6) month period.


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          (4)  Termination by Mutual Written Agreement. This Agreement may also
               be terminated upon any terms and under any condition, which are
               mutually agreed upon in writing by WES and VERASUN.

          (5)  Termination by Bankruptcy, Etc. This Agreement may also be
               terminated immediately and without prior notice by a party as a
               result of the other party's bankruptcy, assignment for the
               benefit of creditors, admission in writing of its inability to
               pay debts generally, or its liquidation, insolvency or
               dissolution.

2.   Quantity and Quality

     A.   VERASUN shall sell to WES the total output of fuel grade ethanol
          ("Ethanol") produced at the VERASUN Aurora, South Dakota, facility
          ("Plant"), currently anticipated to be one hundred (100) million
          gallons per year. Ethanol shall be delivered FOB the Plant, and title
          shall pass as the Ethanol is loaded into transport vessels.

     B.   Such Ethanol shall meet or exceed all industry standards, including
          but not limited to ASTM D.4806 specifications and Williams Pipeline
          Company specifications for E-Grade Denatured Fuel Ethanol.

3.   WES shall:

     A.   Purchase all of the Ethanol produced by VERASUN, at the price outlined
          in Section 5;

     B.   Remit payment to VERASUN for the Ethanol as provided in Section 5; and

     C.   Schedule all loads with VERASUN.

     D.   Extend any alliance volume buying power of discounting to VERASUN.

     E.   Extend railcar freight rates negotiated by WES to VERASUN.

     F.   Participate with VERASUN in a monthly sales strategy call.

4.   VERASUN shall:

     A.   Provide to WES quarterly production forecasts, monthly updates, daily
          plant inventory balances and shipment information;

     B.   Provide to WES specifications and certificates of analysis of the
          Ethanol produced;

     C.   Provide for a minimum of eight days storage on the VERASUN premises;


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     E.   Have meters that provide both gross and net 60 degrees Fahrenheit
          temperature compensated gallons; and

     F.   Establish and participate in monthly sales strategy meetings with WES.

5.   Pricing and Commission

     A.   Sale Price. The price VERASUN shall receive for its Ethanol shall be
          based upon the actual market price received by WES for the sale of the
          Ethanol as set forth below.

     B.   Costs. WES shall deduct all direct costs incurred by WES relating
          exclusively to marketing the Ethanol purchased from VERASUN,
          including, but not limited to, terminal lease charges, throughput
          charges, terminal shrinkage costs (not to exceed .5%), freight
          charges, tariffs, costs of leasing railcars and trucks, government
          taxes and assessments, inspection fees, and other similar costs. These
          costs shall be passed directly to VERASUN without WES markup. WES
          shall not deduct any general or administrative costs incurred in
          marketing the Ethanol. WES shall use commercially reasonable efforts
          to contain costs so as to maximize the net price payable to VERASUN
          for its Ethanol. In the event that VERASUN presents WES with
          alternatives that will reduce such costs, WES shall implement the
          alternatives where commercially reasonable.

     C.   Net Price. Net price is defined as sales price referred in Section
          5(A) less direct costs referred in Section 5(B) ("Net Price"). WES
          shall use commercially reasonable efforts to maximize the Net Price,
          commensurate with prevailing market conditions.

     D.   Establishing Minimum Net Price. VERASUN and WES agree to participate
          in monthly sales strategy meetings at which time VERASUN will
          establish a monthly minimum net price target. WES agrees to make best
          effort to meet or exceed minimum net price targets. If net price
          targets are not attainable:

          (1)  WES must obtain written authorization from VERASUN prior to
               selling below net price target;

          (2)  At VERASUN's request and expense, WES agrees to place VERASUN's
               ethanol in storage until pricing condition can be met

     E.   Commission. WES shall be paid a commission equal to (**) percent (**)
          of the Net Price, as defined in Section 5(C). The total commission
          shall not exceed (**) for the first (**) gallons produced on an annual
          basis. If annual production exceeds (**) gallons, VeraSun agrees to
          pay (**) percent (**) for all ethanol sold over (**) gallons per year.

     G.   Contract Authorization. WES must obtain written authorization from
          VERASUN for all contract sales:

1) This confidential information has been omitted pursuant to a request for
   confidential treatment.

2) The material has been filed separately with the SEC.

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          (1)  Equal to or greater than one (1) million gallons;

          (2)  Where contract length is equal to or greater than six (6) months.

     H.   Payment. For all quantities of ethanol purchased by WES from VERASUN
          during a one-week period beginning on Monday and ending on the
          following Sunday, WES shall pay the Net Price referred to in Section
          5(C) less commissions referred to in Section 5(D), to VERASUN by ACH
          or wire no later than ten (10) business days following the end of said
          one-week period. WES shall pay interest on any delinquent payments at
          the rate of nine percent (9%) per annum, for the duration of the
          delinquency. In addition, WES shall reimburse VERASUN for any attorney
          fees or other costs incurred by VERASUN in collecting delinquent
          amounts owed by WES hereunder. WES is considered in breach of this
          Agreement if the delinquency period extends beyond thirty (30) days.

     I.   Supporting Records. WES shall keep a permanent, accurate set of books
          and records in accordance with generally accepting accounting
          principals with respect to all sales of Ethanol hereunder and all
          costs and commissions associated therewith, and shall make such books
          and records available to VERASUN at WES's office at any time by
          appointment during normal business hours upon at least three (3)
          business days prior written notice. In addition, WES shall provide
          VERASUN by e-mail or fax with supporting documentation regarding the
          calculation of the net sale price with each weekly payment for
          Ethanol.

6.   Indemnity: WES shall indemnify, defend, and hold VERASUN and its
     affiliates, subsidiaries, parents, directors, officers, employees,
     customers, contractors, subcontractors and agents harmless from and against
     any and all claims, losses, awards, judgments, settlements, fines,
     penalties, liabilities, damages, costs or expenses (including reasonable
     Attorney's fees) alleged or incurred on account of any injury to or death
     of persons or damages to property or any other claim to the extent caused
     by or arising out of the negligence or willful misconduct of WES, its
     officers, employees, customers, contractors, subcontractors or agents.

     VERASUN shall indemnify, defend, and hold WES and its affiliates,
     subsidiaries, parents, directors, officers, employees, and agents harmless
     from and against any and all claims, losses, awards, judgments,
     settlements, fines, penalties, liabilities, damages, costs or expenses
     (including reasonable Attorney's fees) alleged or incurred on account of
     any injury to or death of persons or damages to property or any other claim
     to the extent caused by or arising out of the negligence or willful
     misconduct of VERASUN, its officers, employees, customers, agents, or
     contractors. VERASUN shall indemnify and hold WES and its affiliates,
     subsidiaries, parents, directors, officers, employees, customers and agents
     harmless from and against any and all claims, losses, awards, judgments,
     settlements, fines, penalties, liabilities, damages, costs or expenses
     (including reasonable Attorney's fees) from any defects in the Ethanol
     caused by VERASUN.

7.   Independent Contractor: It is expressly understood that the relationship of
     WES to VERASUN is that of an independent contractor and nothing contained
     herein shall be construed to create any partnership, agency, or
     employer/employee relationship. WES may freely choose the customers from
     whom business shall be solicited and the time and place for solicitation,
     except as otherwise provided in this Agreement.


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8.   Notices: Any notices required to be given under this Agreement shall be in
     writing and shall be deemed given upon personal delivery to the party to be
     notified; on the third day after deposit with the United States Postal
     Service, by registered or certified mail, postage prepaid; or upon
     confirmation if sent by telex, facsimile machine or other means of
     telecommunication that transmits or produces a written record of the
     message so sent. Notices shall be sent addressed as follows:

     VERASUN:   VERASUN Energy Corporation
                100 22nd Avenue
                Suite # 103
                Brookings, SD 57006
                Attn: Donald Endres, CEO
                Telephone: 605-696-7200
                Fax: 605-696-7250

     WES:       Williams Bio-Energy
                P. O. Box 10
                Pekin, IL 61555
                Attn: Ronald Miller
                Telephone: 309-347-9388
                Fax: 309-347-8541

9.   Insurance: The Parties shall maintain, at all times while this Agreement is