Document:

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                                                                   Exhibit 10.20

                               SECURITY AGREEMENT

     THIS SECURITY AGREEMENT, is given this 16th day of December, 2005, by Red
Trail Energy, LLC, a North Dakota limited liability company ("DEBTOR") to FIRST
NATIONAL BANK OF OMAHA, a national banking association, with principal offices
at 1620 Dodge St Stop 1050, Omaha, Nebraska 68197-1050 ("SECURED PARTY").

     WHEREAS, DEBTOR has borrowed from SECURED PARTY the sum of Fifty Eight
Million Seven Hundred Eleven Thousand Seven Hundred Forty Dollars
($59,711,740.00), herein called the "LOAN," and has executed and delivered to
SECURED PARTY a Construction Loan Agreement ("LOAN AGREEMENT"), a Promissory
Note ("NOTES") for the principal sum of the Construction Loan amount, with
interest therein expressed, the Revolving Loan amount with interest therein
expressed, and the Line of Credit Note with interest therein expressed, a Deed
of Trust and Assignment of Rents of even date therewith (herein called the
"MORTGAGES"), securing said NOTES and covering all right, title and interest of
the Debtor in and to certain real estate and improvements ("REAL ESTATE")
described on Exhibit A hereto, by this reference made a part hereof, which is
set forth in the MORTGAGES, together with all easements, rights and
appurtenances thereunto belonging, and

     WHEREAS, SECURED PARTY has required, as additional security for said LOAN,
a first lien upon all collateral, as hereinafter defined, now owned or hereafter
acquired by DEBTOR, and DEBTOR desires to grant to SECURED PARTY a first lien
upon said property as additional security for said LOAN and the LOAN AGREEMENT.

A. NOW, THEREFORE, in consideration of the consummation of said LOAN and the
LOAN AGREEMENT and for other good and valuable consideration, the receipt and
sufficiency whereof are hereby acknowledged, DEBTOR, for itself, its successors
and assigns, has bargained and sold, and by these presents does grant, bargain,
sell and convey unto SECURED PARTY a security interest in the following
collateral and the products and proceeds thereof:

     1. Accounts, Chattel Paper, Commercial Tort Claims, Contracts, Contract
     Rights, Documents, Equipment, Fixtures, General Intangibles, Goods,
     Health-care-insurance receivables/accounts, Instruments, Intellectual
     Property, Inventory, Investment Property, Letter-of-credit rights, Payment
     Intangibles, Tangible Chattel Paper, Rights as seller of Goods and rights
     returned or repossessed goods; and all Records pertaining to Collateral.

     2. All of the rents, royalties, issues and profits of the real estate and
     improvements described in the MORTGAGES, or arising from the use or
     enjoyment of all or any portion thereof or from any lease, license,
     concession, occupancy agreement or other agreement pertaining thereto.

     3. All building materials and supplies now or hereafter placed on the REAL
     ESTATE or in the improvements owned by DEBTOR.

     4. All proceeds of the conversion, voluntary or involuntary, of any of the
     foregoing into cash or liquidated claims, including, without limitation,
     proceeds of insurance and condemnation awards.

B. This Security Agreement is made for the purpose of additionally securing:

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     1. The payment of the indebtedness evidenced by the NOTES.

     2. The payment of all other sums, and interest thereon, becoming due and
     payable to SECURED PARTY under the provisions hereof or under the
     provisions of the NOTES and MORTGAGES.

     3. The performance and discharge of each and every obligation, covenant and
     agreement of the DEBTOR herein, in said NOTES and MORTGAGES, and the LOAN
     AGREEMENT, and in any other security agreements executed by the DEBTOR
     evidencing or securing the LOAN, or incorporated by reference in any of
     them.

     4. The repayment of all sums or amounts that are advanced or extended by
     SECURED PARTY, its successors and assigns, for the maintenance or
     preservation of the collateral, or any part thereof.

     5. The payment of all amounts due under all extensions or renewals, and
     successive extensions or renewals, of the NOTES, or the indebtedness
     represented thereby, or of any other or further indebtedness at any time
     owing by DEBTOR to SECURED PARTY, however the same may be advanced, and in
     whatever form it may be, whether represented by notes, drafts, open
     accounts or otherwise, and all interest thereon, the payment of which this
     Agreement shall stand as continuing security until full and complete
     payment shall have been made.

C. DEBTOR declares and warrants to SECURED PARTY that DEBTOR is (or upon
installation of the collateral will be) the absolute owner and in possession of
all the collateral and that said property is (or upon installation of said
property will be) free and clear of all prior liens, encumbrances, security
interests and adverse claims, and DEBTOR shall and will warrant and defend the
title to said property against the claims of all persons whomsoever. Without the
written consent of SECURED PARTY, DEBTOR will not permit any lien, encumbrance,
security interest or adverse claim to attach to the collateral. DEBTOR further
warrants that no financing statement covering the collateral is on file in any
public office and at the request of SECURED PARTY, DEBTOR will join SECURED
PARTY in executing one or more financing statements pursuant to the North Dakota
Uniform Commercial Code, in a form satisfactory to SECURED PARTY, and DEBTOR
will pay the cost of filing in all public offices wherever filing is deemed
necessary by SECURED PARTY.

D. Except in the ordinary course of business, DEBTOR shall not have the right,
power or authority, and will not remove from the location described in Exhibit A
any of the collateral without the prior written consent of SECURED PARTY; any
such removal, without such consent to be construed as a breach hereof, the same
as if a default were made in the payment of any amount secured hereunder, and
the entire amount then unpaid shall immediately become due and payable. If
DEBTOR fails to make any payment, or perform any act which it is obligated to
perform under the provisions of this Agreement, SECURED PARTY, without demand or
notice to DEBTOR, or any successor in interest of DEBTOR, may make such payment
or perform such acts and incur any liability or expend whatever amounts in its
absolute discretion as it may deem necessary therefor, and all sums incurred or
expended by SECURED PARTY, or its successors, under the terms of this Agreement,
shall immediately become due and payable by DEBTOR to SECURED PARTY, or its
successor in interest, when so incurred or expended, and shall bear interest at
the rate provided for in the LOAN AGREEMENT and shall be secured hereby.

E. The parties recognize that after the collateral is installed in the REAL
ESTATE, portions thereof may become inadequate, obsolete, worn out, unsuitable
or unnecessary in the operation of the business operated upon the REAL ESTATE.
DEBTOR shall promptly renew, repair, or replace any inadequate,

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obsolete, worn out or unsuitable property in which this security interest is
given if it is material and necessary to the operation of the DEBTOR's Ethanol
Plant.

F. Upon the happening and continuance of any one or more of the EVENTS OF
DEFAULT as defined in the LOAN AGREEMENT or MORTGAGES, SECURED PARTY may
exercise any one or more of the following rights, or any combination of any of
the following rights:

     1. SECURED PARTY, without notice or demand, and without the necessity of
     having a receiver appointed, and without regard to the adequacy or
     inadequacy of any security for the indebtedness, or the solvency or
     insolvency of the DEBTOR, may, at any time, take possession of the
     collateral and repair, care for, lease or manage the said property and
     perform any act necessary to collect the rents, issues, income and profits
     thereof and apply the proceeds in the manner specified herein upon sale of
     the collateral.

     2. SECURED PARTY may declare all sums secured hereby immediately due and
     payable and may exercise any or all of the rights and remedies available to
     a SECURED PARTY under the North Dakota Uniform Commercial Code and it may,
     at its option, enter upon the premises where said property may be and take
     such measures as to SECURED PARTY may be deemed necessary or proper for the
     care or protection thereof and remove and/or dispose of said property at
     either public or private sale (the DEBTOR hereby expressly waiving demand).
     SECURED PARTY, its successors or assigns, may become the purchaser and from
     the proceeds of said sale, retain all costs and charges (including
     attorney's fees) incurred in the taking or sale of said property and in the
     care and protection thereof, and may apply the balance toward the payment
     of all sums due SECURED PARTY and secured hereby and shall dispose of the
     surplus remaining as provided by law. Any requirement of reasonable notice
     of and disposition of the collateral shall be satisfied if such notice is
     mailed by regular mail to the address of DEBTOR shown in this Agreement, at
     least five days prior to the time of such public or private sale.

     3. SECURED PARTY, its successors or assigns, shall be entitled, in addition
     to the foregoing, as a matter of right, to the appointment of a receiver by
     a court of competent jurisdiction to assist it in performing and doing any
     acts hereinabove set forth. All expenses of such receiver (including
     attorney's fees) shall likewise become immediately due and payable by
     DEBTOR to SECURED PARTY, or its successors in interest, shall bear interest
     at the rate provided by the NOTES, and shall be secured hereby.

     4. The taking of possession of the collateral and the receipt of any income
     provided for herein shall not cure or waive any default, or notice of
     default, or invalidate any act done pursuant to such notice.

G. Failure on the part of SECURED PARTY to demand the entire payment after the
happening of any default shall not be deemed a waiver by SECURED PARTY of its
rights to make immediate demand for the entire amount remaining unpaid, or to
exercise any right or remedy, or combination thereof, as provided in this
Agreement; and any payments made subsequent to a default, or the acceptance of
partial payment, shall not be deemed a waiver of such rights. The lien of this
Agreement shall continue until payment in full of the amounts secured by this
Agreement have been completed.

H. This Agreement shall be construed to be a lien against (1) any like or
similar property hereinafter acquired by DEBTOR, either as additions to, or in
the place of, the collateral subject to this Agreement, and whether the
additions or substitutions be made with or without the knowledge or consent of
SECURED PARTY, and (2) the proceeds of such after-acquired property.

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I. All remedies allowed SECURED PARTY under applicable law and under the terms
of this Agreement are, and shall be, concurrent and cumulative, and may be
exercised and enforced as hereinabove and as by law provided, without reference
to the time or manner of foreclosure or enforcement of any other security for
said indebtedness or obligations, whether held by deed of trust, mortgage,
pledge, security agreement or otherwise.

J. In this Agreement, whenever the context so requires, the masculine gender
includes the feminine and/or neuter, and the singular number includes the
plural, and the term "SECURED PARTY" shall include any future holder, including
pledge, of the NOTES secured hereby.

K. SECURED PARTY may, at any time, or from time to time, without liability
therefor and without notice, upon request of DEBTOR, and without affecting the
personal liability of any person for the payment of the indebtedness secured
hereby, release any part of the collateral or join in any extension agreement or
subordination agreement in connection herewith. SECURED PARTY shall have the
right to inspect the collateral at any time.

     IN WITNESS WHEREOF, DEBTOR has caused these presents to be executed the day
and year first above written.

Red Trail Energy, LLC:

By: /s/ Ambrose R. Hoff
    ---------------------------------
Title: President

And

By: /s/ William N. DuToit
    ---------------------------------
Title: Treasurer

STATE OF North Dakota)
                     )ss.
COUNTY OF STARK      )

     On this 16 day of December, 2005, before me, the undersigned, a Notary
Public, personally appeared Ambrose Hoff, President of Red Trail Energy, LLC, a
North Dakota limited liability company, on behalf of said entity, who executed
the foregoing instrument, and acknowledged that he executed the same as
his voluntary act and deed and that of the company.

                                        /s/ Deell Hoff
                                        ----------------------------------------
                                        Notary Public

                               [DEELL HOFF STAMP]

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STATE OF North Dakota)
                     )ss.
COUNTY OF STARK      )

     On this 16 day of December, 2005, before me, the undersigned, a Notary
Public, personally appeared William DuToit, Tres. of Red Trail Energy, LLC, a
North Dakota limited liability company, on behalf of said entity, who executed
the foregoing instrument, and acknowledged that he executed the same as his
voluntary act and deed and that of the company.

                                        /s/ Deell Hoff
                                        ----------------------------------------
                                        Notary Public

                               [DEELL HOFF STAMP]

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                                    EXHIBIT A

                                LEGAL DESCRIPTION

TRACT 1:

A TRACT OF LAND LOCATED IN THE SOUTHWEST QUARTER (SW1/4) OF SECTION 4, TOWNSHIP
139 NORTH, RANGE 92 WEST OF THE 5th PRINCIPAL MERIDIAN, STARK COUNTY, NORTH
DAKOTA. Being more particularly described as follows:

All that portion of said Southwest Quarter lying South of the southerly 200 foot
right of way line of the Burlington Northern / Santa Fe Railroad as surveyed and
constructed across said Southwest Quarter of Section 4, except the west 100.00
feet and the south 850.00 feet of the west 920.00 feet of said Southwest Quarter
of Section 4

TRACT 2:

A TRACT OF LAND IN THE SE1/4 OF SECTION 4, TOWNSHIP 139 NORTH, RANGE 92 WEST OF
THE 5th P.M., STARK COUNTY, NORTH DAKOTA, more particularly described as
follows:

All that portion of said SE1/4 lying south of the southerly 200 foot right of
way line of the Burlington Northern / Santa Fe Railroad as surveyed and
constructed across the said SE1/4 of Section 4

TRACT 3:

A tract of land located in the South Half (S1/2) of Section 4, Township 139
North, Range 92 West of the 5th Principal Meridian, Stark County, North Dakota,
being more particularly described as follows:

The southerly 150.00 feet of the southerly 200.00 feet of right of way for the
Burlington Northern / Santa Fe Railroad as surveyed and constructed across said
South Half of Section 4. Said tract contains 16.87 acres.

TRACT 4:

A tract of land located in the Northeast Quarter of the Northeast Quarter (NE1/4
NE1/4) of Section 9, Township 139 North, Range 92 West of the 5th Principal
Meridian, Stark County, North Dakota, being more particularly described as
follows:

The southerly 150.00 feet of the southerly 200.00 feet of right of way for the
Burlington Northern / Santa Fe Railroad as surveyed and constructed across said
Northeast Quarter of the Northeast Quarter of Section 9. Said Tract contains
2.79 acres.

TRACT 5:

A tract of land located in the Northwest, Northeast, and Southeast Quarters of
Section 10, Township 139 North, Range 92 West of the 5th Principal Meridian,
Stark County, North Dakota, being more particularly described as follows:

The southerly 150.00 feet of the southerly 200.00 feet of right of way for the
Burlington Northern / Santa Fe Railroad as surveyed and constructed across said
Northwest Quarter, the Northeast Quarter and the Southeast Quarter of Section
10. Said tract contains 22.05 acres.

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                                                                   Exhibit 10.21

                                CONTROL AGREEMENT
               REGARDING SECURITY INTEREST IN INVESTMENT PROPERTY

     This Agreement, made as of the 16th day of December, 2005, by and between
First National Bank of Omaha, a national banking association established in
Omaha Nebraska ("BANK"), Red Trail Energy, LLC, a North Dakota limited liability
company ("CUSTOMER"), and First National Capital Markets, Inc. ("COMPANY"), a
Nebraska corporation with offices at 1620 Dodge St., Omaha, Nebraska.

                                    RECITALS

     A. CUSTOMER is indebted to BANK as the result of one or more promissory
notes, or other evidence of indebtedness. Such indebtedness, whether resulting
from a promissory note, guaranty, letter of credit, or any other document or
cause, is herein called an "OBLIGATION".

     B. For purposes of this agreement, all capitalized terms not otherwise
defined herein have the same meanings as defined in Nebraska Uniform Commercial
Code.

     C. CUSTOMER has provided BANK security interests in the COLLATERAL (as
defined below) and CUSTOMER desires to provide BANK with CONTROL (as such term
is defined in Nebraska Uniform Commercial Code Section 8-106) over the
COLLATERAL (as defined below).

     Now, therefore, the parties hereto agree as follows:

     1. The COMPANY represents and agrees that: (i) it has established and is
maintaining on its books and records the account number 23200041 in the name of
BORROWER, (said account, together with any replacements thereof or substitutions
therefore, collectively the ACCOUNT) and (ii) the ACCOUNT is a "securities
account" (within the meaning of Section 8-501(a) of the UCC) in respect of
which the COMPANY is a "securities intermediary" (within the meaning of Section
8-102(a)(14) of the UCC) and the BANK is the "entitlement holder" (within the
meaning of Section 8-102(a)(7) of the UCC).

     2. The COMPANY hereby agrees that each item of property (whether cash, a
security, an instrument or any other property whatsoever) credited to the
ACCOUNT shall be treated as FINANCIAL ASSETS under Article 8 of the UCC (the
ACCOUNT and the FINANCIAL ASSETS credited thereto shall be hereafter referred to
as the COLLATERAL).

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     3. The COMPANY agrees that, if there is any conflict between this Agreement
and any other agreement relating to the ACCOUNT, the provisions of this
Agreement shall control.

     4. COMPANY agrees that it will comply with INSTRUCTIONS and ENTITLEMENT
ORDERS originated by BANK as to the COLLATERAL, without further consent of
CUSTOMER. Until otherwise instructed, CUSTOMER is to receive any cash dividends
attributable to the COLLATERAL.

     5. Notwithstanding the provisions of paragraph 4, above, CUSTOMER retains
the right to originate instructions to COMPANY as to substitutions for the
COLLATERAL, until BANK provides written notice to COMPANY of a default by
CUSTOMER as to any OBLIGATION, following receipt of which only BANK may
originate instructions to COMPANY as to the COLLATERAL. After the Company
receives notice from the BANK that a default has occurred, the Company agrees
that it will no longer comply with ENTITLEMENT ORDERS originated by, or other
directions or instructions received from, the CUSTOMER with respect to the
ACCOUNT or cash, securities or other property credited thereto.

     6. This Agreement is executed in Nebraska and is subject to the laws of
Nebraska, including the Nebraska Uniform Commercial Code. This Agreement is
effective until terminated by a written notice executed by BANK delivered to
COMPANY, or until the COLLATERAL is no longer registered to or owned by
CUSTOMER.

     7. COMPANY represents that it has not and covenants that it will not agree
to comply with any instructions or entitlement orders with respect to the
ACCOUNT other than as set forth herein.

IN WITNESS WHEREOF, the parties have executed this agreement as of the date
first set forth above.

BANK
First National Bank of Omaha

By /s/ Natalie E. Mason
   ----------------------------------
   Natalie E. Mason, Commercial Loan
   Officer

COMPANY
First National Capital Markets, Inc.

By /s/ DAVID COTA
   ----------------------------------
     DAVID COTA
Its: President

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CUSTOMER
Red Trail Energy, LLC

By /s/ Ambrose R. Hoff
   ----------------------------------
       Ambrose R. Hoff
Title: President

And

By /s/ William Dutoit
   ----------------------------------
       William Dutoit
Title: Treasurer

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