AMENDMENT TO  CREDIT AGREEMENT
                         ------------------------------


     THIS AMENDMENT is made as of March 30, 1999 by and among BOSTON BEER
COMPANY LIMITED PARTNERSHIP (the "Partnership") and THE BOSTON BEER COMPANY,
                                  -----------                              
INC. (the "Corporation") (collectively, the "Borrowers", and individually, a
           -----------                       ---------                     
"Borrower")'; and FLEET NATIONAL BANK (the "Bank").
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                                    RECITALS
                                    --------

     A.   The Bank and the Borrowers are parties to a Credit Agreement dated as
of March 21, 1997, as modified by a letter agreement dated July 11, 1997 (as
modified, the "Loan Agreement").  Capitalized terms used herein without
               --------------                                         
definition have the meanings assigned to them in the Loan Agreement.

    B.    The Borrowers have requested that, among other things, the Bank (i)
extend the Expiration Date, the Conversion Date and the Maturity Date and (ii)
reduce the interest rates applicable to the Loans.

     C.   Subject to certain terms and conditions, the Bank is willing to agree
to the same, as hereinafter set forth.

     NOW THEREFORE, for good and valuable consideration, the receipt and
sufficiency of which is hereby acknowledged, the parties hereto agree as
follows:

I.   Amendments to Loan Agreement.
     ----------------------------

     A.   Extension of Dates in Section 1.1.  The "Expiration Date" as defined
          ---------------------------------                                  
in Section 1.1(a) is hereby extended to mean March 31, 2004.  The "Conversion
Date" as defined in Section 1.1(b) is hereby extended to mean March 31, 2002.
The date on which quarterly installments of Term Loan Principal repayments shall
commence under Section 1.1(c) is hereby extended to mean June 30, 2002 and
"Maturity Date" as defined in Section 1.1(c) is hereby extended to mean March
31, 2007.

     B.   Interest Rates.  Section 1.3(a) is hereby deleted in its entirety and
          --------------                                                      
replace with the following:

     "(a) Subject to this Agreement, the Borrowers may elect an interest rate
          for each Revolving Loans A and Revolving Loans B based on either (i)
          the Alternative Prime Rate or (ii) the applicable Libor Rate (as
          defined on Schedule B hereto) plus .45%.  Subject to the terms and
                     ----------                                            
          conditions of this Agreement, the Borrowers may elect an interest rate
          for the Term Loan based on either (i) the Alternative Prime Rate or
          (ii) the applicable Libor Rate plus .70%.  Each Prime Rate Loan shall
          bear interest on the outstanding principal amount thereof at a rate
          per annum equal to the Prime Rate (which rate shall change
          contemporaneously with any change in the Prime Rate), payable on the
          last day of each fiscal quarter, commencing on March 31, 1999, and
          when such Prime Rate Loan is due (whether at maturity, by reason of
          acceleration or otherwise).  Libor Loans shall bear interest, and
          otherwise be governed, in accordance with Schedule B (the "Libor
                                                    ----------       -----
          Terms")."

     C.   Use of Proceeds.  Section 1.10 is hereby amended to permit proceeds of
          ---------------                                                      
up to $10,000,000 in the aggregate to be used for Permitted Acquisitions.

     D.   Net Worth Covenant.  Section 5.1(a) is hereby deleted in its entirety
          ------------------                                                  
and replaced with the following:

     "(a) Maintain at all times during the period from March 31, 1999 through
          June 29, 1999 a Tangible Net Worth of the Corporation of not less than
          $70,000,000, plus 50% of the positive Net Income (with no reduction
          for losses) for the fiscal quarter ended March 31, 1999; and,
          thereafter maintain Tangible Net Worth of the Corporation at all times
          during each fiscal quarter of at least (i) the minimum amount of
          Tangible Net Worth required hereunder as of the last day of the
          immediately
<PAGE>

          preceding fiscal quarter, plus (ii) 50% of the positive Net Income
          (with no reduction for losses) for such immediately preceding fiscal
          quarter, plus (iii) 100% of Net Equity Proceeds received by the
          Corporation during such fiscal quarter."

     E.   Profitability.  Section 5.1(d) is hereby deleted in its entirety and
          -------------                                                      
replaced with the following:

     "(d) As to the Corporation, (i) for any trailing four consecutive fiscal
          quarter-period earn Net Income of at least $1.00 and (ii) not have two
          consecutive fiscal quarters in which Net Income for each such fiscal
          quarter is less than $0."

     F.   Indebtedness.  Section 6.1(b) is deleted in its entirety and replaced
          ------------                                                        
with the following:

     "(b) Indebtedness represented by amortization of the signing payment
          received by the Corporation under its 1998 glass bottle contract;"

     G.   New Provisions.  The following provision is added to the Loan
          --------------                                              
Agreement as Section 8.13.

     "8.13 Miscellaneous
           -------------

     (a)  The Bank may assign its rights and interests under this Agreement, the
          Notes and the other Loan Documents and delegate its obligations
          hereunder and thereunder, in whole or in part; provided that in
          connection with any such assignment, the assignee shall assume such
          rights, interests and obligations in writing. The Bank may at any time
          pledge all or any portion of its rights under any Loan Document
          (including any portion of the Notes) to any of the 12 Federal Reserve
          Banks organized under Section 4 of the Federal Reserve Act, 12 U.S.C.
          Section 341. No such pledge or the enforcement thereof shall release
          the Bank from its obligations under any of the Loan Documents. The
          Bank shall have the unrestricted right at any time and from time to
          time, and without the consent of or notice to the Borrowers to grant
          to one or more banks or other financial institutions (each, a
          "Participant") participating interests in the Bank's obligation to
          ------------                                                     
          lend hereunder and/or any or all of the Obligations.  In the event of
          any such grant by the Bank of a participating interest to a
          Participant, whether or not upon notice to the Borrowers, the Bank
          shall remain responsible for the performance of its obligations
          hereunder and the Borrowers shall continue to deal solely and directly
          with the Bank in connection with its rights and obligations hereunder.
          Each of the Borrowers authorizes the Bank to disclose to any
          participant or assignee any prospective participant or assignee any
          and all information in the Bank's possession concerning the Borrowers
          which has been delivered to the Bank by or on behalf of the Borrowers
          pursuant to this Agreement or which has been delivered to the Bank by
          or on behalf of the Borrowers in connection with the Bank's credit
          evaluation prior to becoming a party to this Agreement.

     (b)  Upon receipt of an appropriate and reasonably acceptable affidavit of
          an officer of the Bank as to the loss, theft, destruction or
          mutilation of the any Note or of any other Loan Document which is not
          of public record and, in the case of any such mutilation, upon
          surrender and cancellation of such Note or other Loan Document, the
          Borrowers will issue, in lieu thereof, a replacement Note or other
          Loan Document in the same principal amount and in any event of like
          tenor.

     (c)  All agreements between any one or more of the Borrowers (on the one
          hand) and the Bank (on the other hand) are hereby expressly limited so
          that in no contingency or event whatsoever, whether by reason of
          acceleration of maturity of the Notes or otherwise, shall the amount
          paid or agreed to be paid to the Bank for the use or the forbearance
          of the Obligations represented by the Notes exceed the maximum
          permissible under applicable law.  In this regard, it is expressly
          agreed that it is the intent of the Borrowers and the Bank, in the
          execution, delivery and acceptance of the Notes, to contract in strict
          compliance with the laws of the Commonwealth of Massachusetts.  If,
          under any circumstances whatsoever, performance or fulfillment of any
          provision of the Notes or any of the other Loan Documents at the time
          such provision is to be performed or fulfilled shall involve exceeding
          the limit of validity prescribed by applicable law, then the
          obligation so to be performed or fulfilled shall be reduced
          automatically to the limits of such validity, and if under any
<PAGE>

          circumstances whatsoever the Bank should ever receive as interest an
          amount which would exceed the highest lawful rate, such amount which
          would be excessive interest shall be applied to the reduction of the
          principal balance evidenced by the Notes and not to the payment of
          interest.  The provisions of this Section 8.13(c) shall control every
          other provision of this Agreement and of the Notes."

     H.   Amended Definitions.  The definitions of "Permitted Acquisition" and
          -------------------                                                
"Prime Rate" in Schedule A are amended to read in their entirety as follows:

          Permitted Acquisitions:  any acquisition of stock or assets by the
          ----------------------                                           
          Corporation which has met the following conditions:  (a) the aggregate
          amount of proceeds of the Loans used in all such acquisitions since
          the date of this Agreement shall not exceed $10,000,000, (b) the
          aggregate amount paid in cash or cash equivalents by the Borrowers and
          their Subsidiaries in connection with all such acquisitions since the
          date of this Agreement (whether or not proceeds of the Loans) shall
          not exceed $20,000,000, (c) after giving effect to such acquisition,
          on a pro forma basis as of the most recently ended fiscal quarter, the
               --- -----                                                       
          Borrowers shall be in full compliance with all of its obligations set
          forth in Section 5 of this Agreement, (d) if such acquisition is a
          stock acquisition and the acquired company or companies is not being
          merged into the Corporation simultaneously and is or becomes a
          Material Subsidiary, such acquired company or companies shall prior to
          or upon becoming a Material Subsidiary execute an unlimited guaranty
          in form satisfactory to the Bank, guaranteeing all existing and future
          obligation of the Borrowers to the Bank, (e)  prior notice of such
          acquisition shall have been delivered to the Bank, describing the
          terms of such acquisition, including the purchase price thereof, and
          whether the acquired company or companies are or are intended to
          become Material Subsidiaries, and (f) no Default shall exist hereunder
          or result from such acquisition.  The Bank acknowledges that the
          Schoenling Brewery acquisition which closed in March, 1997 (and the
          subsequent real property acquisition relating thereto) are Permitted
          Acquisitions not included in the $10,000,000 and $20,000,000
          thresholds set forth above.

          "Prime Rate:  The variable per annum rate of interest so designated
           ----------                                                       
          from time to time by the Bank as its prime rate.  The Prime Rate is a
          reference rate and does not necessarily represent the lowest or best
          rate being charged to any customer."

     I.   New Definition:  "Net Equity Proceeds."  The definition of the term
          -------------------------------------                             
"Net Equity Proceeds" is hereby added to Schedule A in the proper alphabetical
order:

          "Net Equity Proceeds":  The cash proceeds (net of reasonable out-of-
           -------------------                                              
          pocket fees and expenses) received by the Corporation or any of its
          Subsidiaries in connection with any issuance by the Corporation or any
          its Subsidiaries after March 31, 1999 of any shares of its capital
          stock, other equity interests or options, warrants or other purchase
          rights to acquire such capital stock or other equity interests to, or
          receipt of a capital contribution from, any Person (other than an
          officer, employee or director of the Borrower or any its Subsidiaries
          or the Borrower with respect to capital contributions to such
          Subsidiaries)."

     J.   Libor Terms.  The following changes are made to Schedule B regarding
          -----------                                     ----------         
Libor Terms:

     (a)  The definition of "Libor Base Rate" and "Adjusted Libor Rate are
          hereby deleted in their entirety.

     (b)  All references in the Loan Agreement to "Libor Base Rate" or "Adjusted
          Libor Rate" shall hereafter mean and be a reference to the "Libor
          Rate".

     (c)  The following definition of "Libor Rate" is added to Schedule B:

          Libor  Rate:  With respect to each Interest Period for a Libor Loan,
          -----------                                                        
          that rate per annum (rounded upward, if necessary, to the nearest
          1/32nd of one percent) which represents the offered rate for deposits
          in U.S. Dollars, for a period of time comparable to such Interest
          Period, which appears on the Telerate page 3750 as of 11:00 a.m.
          (London time) on that day that is two London Banking
<PAGE>

          Days preceding the first day of such Interest Period; provided,
          however, that if the rate described above does not appear on the
          Telerate System on any applicable interest determination date, the
          Libor Rate for such Interest Period shall be the rate (rounded upwards
          as described above, if necessary) for deposits in dollars for a period
          substantially equal to such Interest Period shown on the Reuters Page
          "LIBO" (or such other page as may replace the LIBO Page on that
          service for the purpose of displaying such rates), as of 11:00 a.m.
          (London Time), on that day that is two London Banking Days prior to
          the beginning of such Interest Period. "London Banking Day" shall mean
                                                  ------------------
          any date on which commercial banks are open for business in London. If
          both the Telerate and Reuters systems are unavailable, then the Libor
          Rate for any Interest Period will be determined on the basis of the
          offered rates for deposits in U.S. Dollars for a period of time
          comparable to such Interest Period which are offered by four major
          banks in the London interbank market at approximately 11:00 a.m.,
          London time, on that day that is two London Banking Days preceding the
          first day of such Interest Period, as selected by the Bank. The
          principal London office of each of four major London banks will be
          requested to provide a quotation of its U.S. Dollar deposit offered
          rate. If at least two such quotations are provided, the rate for that
          date will be the arithmetic mean of the quotations. If fewer than two
          quotations are provided as requested, the rate for that date will be
          determined on the basis of the rates quoted for loans in U.S. Dollars
          to leading European banks for a period of time comparable to such
          Interest Period offered by major banks in New York City at
          approximately 11:00 a.m., New York City time, on that day that is two
          London Banking Days preceding the first day of such Interest Period.
          In the event that the Bank is unable to obtain any such quotation as
          provided above, it will be deemed that the Libor Rate for the proposed
          Interest Period cannot be determined. The Bank shall give prompt
          notice to the Borrowers of the Libor Rate as determined for each Libor
          Loan and such notice shall be conclusive and binding, absent manifest
          error. In the event that the Board of Governors of the Federal Reserve
          System shall impose a Libor Reserve Requirement with respect to Libor
          deposits of the Bank, then for any period during which such Libor
          Reserve Requirement shall apply, the Libor Rate shall be equal to the
          amount determined above, divided by an amount equal to 1 minus the
          Libor Reserve Requirement. The Libor Rate shall be adjusted
          automatically on and as of the effective date of any change in the
          Libor Reserve Requirement with respect to the Bank.

II.  No Further Amendments.
     ---------------------

     Except as specifically amended hereby, the Loan Agreement shall remain
unmodified and in full force and effect and is hereby ratified and affirmed in
all respects, and the indebtedness of the Borrowers to the Bank evidenced
thereby and by the Notes is hereby reaffirmed in all respects.  On and after the
date hereof, each reference in the Loan Agreement to "this Agreement",
"hereunder", "hereof", or words of like import referring to the Loan Agreement,
shall mean and be a reference to the Loan Agreement as amended by this
Amendment, and each reference in any of the Loan Documents, to the Loan
Agreement, "thereunder", "thereof", or words of like import referring to the
Loan Agreement shall mean a reference to the Loan Agreement as amended by this
Amendment.

III. Certain Representations of the Borrowers.
     ----------------------------------------

     As a material inducement to the Bank to enter into this Amendment, the
Borrowers hereby represent and warrant to the Bank (which representations and
warranties shall survive the delivery of this Amendment), after giving effect to
this Amendment, as follows:

     A.   The execution and delivery of this Amendment has been duly authorized
by all requisite corporate action on the part of the Borrower.

     B.   The representations and warranties contained in Section 4 of the Loan
Agreement are true and correct in all material respects on and as of the date of
this Amendment as though made at and as of such date (except to the extent that
such representations and warranties expressly relate to an earlier date or
except to the extent variations therefrom have been permitted under the terms of
the Loan Agreement or otherwise in writing by the Bank).  No material adverse
change has occurred in the assets, liabilities, financial condition, business or
prospects of Borrower from that disclosed in the financial statements most
recently furnished to the Bank pursuant to
<PAGE>

Sections 4.1(a) or (b) to the Loan Agreement. To the knowledge of the Borrower,
no Default has occurred and is continuing.

     C.   This Amendment constitutes the legal, valid and binding obligation of
each Borrower, enforceable against each Borrower in accordance with its terms,
subject to bankruptcy, insolvency, reorganization, moratorium and similar laws
affecting the rights and remedies of creditors generally or the application of
principles of equity, whether in any action at law or proceeding in equity, and
subject to the availability of the remedy of specific performance or of any
other equitable remedy or relief to enforce any right thereunder.

IV.  Miscellaneous.
     -------------

     A.   The Borrowers represent, warrant, and agree that the Borrowers have no
claims, defenses, counterclaims, or offsets against the Bank in connection with
the Loan Agreement or the Obligations and, to the extent that any such claim,
defense, counterclaim, or offset may exist, the Borrower hereby affirmatively
WAIVES AND RELEASES the Bank from the same.

     B.   As provided in the Loan Agreement, the Borrowers agree to reimburse
the Bank upon demand for all reasonable out-of-pocket costs, charges,
liabilities, taxes and expenses of the Bank (including reasonable fees and
disbursements of counsel to the Bank) in connection with the (a) preparation,
negotiation, interpretation, execution and delivery of this Amendment and any
other agreements, instruments and documents executed pursuant or relating
hereto, and (b) any enforcement hereof.

     C.   This Amendment shall be governed by and construed in accordance with
the laws of the Commonwealth of Massachusetts.

     D.   This Amendment may be executed by the parties hereto in several
counterparts hereof and by the different parties hereto on separate counterparts
hereof, all of which counterparts shall together constitute one and the same
agreement.



                    **The Next Page is the Signature Page**
<PAGE>

     IN WITNESS WHEREOF, the Bank and the Borrowers have caused this Amendment
to be duly executed as a sealed instrument by their duly authorized
representatives, all as of the day and year first above written.

                             THE BOSTON BEER COMPANY, INC.


                             By:                  /s/ Alfred W. Rossow, Jr.
                                                  Treasurer and CFO


                             BOSTON BEER COMPANY LIMITED PARTNERSHIP

                             By:  Boston Brewing Company, Inc., its General
                                  Partner


                                     By:             /s/ Alfred W. Rossow, Jr.
                                     Title:          Vice President



                             FLEET NATIONAL BANK


                             By:                     /s/ Susan Mason
                                                     Vice President
<PAGE>

                             GUARANTOR CONFIRMATION
                             ----------------------

          The undersigned being guarantor of the Obligations (as defined in a
certain Unlimited Guaranty dated March 21, 1997) of the Borrowers to the Bank
and intending to be legally bound thereunder hereby agrees and consents to the
above Amendment.  The undersigned hereby further confirms and reaffirms, all and
singular, the terms of such Unlimited Guaranty.

Dated as of March 30, 1999.

                                              SAMUEL ADAMS BREWERY COMPANY, LTD.
                                                                               


                                               By:    /s/ Alfred W. Rossow, Jr.
                                                      Treasurer and CFO

Source: OneCLE Business Contracts.