<SEC-DOCUMENT>0001562180-22-002710.txt : 20220317
<SEC-HEADER>0001562180-22-002710.hdr.sgml : 20220317
<ACCEPTANCE-DATETIME>20220317160142
ACCESSION NUMBER:		0001562180-22-002710
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20220316
FILED AS OF DATE:		20220317
DATE AS OF CHANGE:		20220317

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Murphy Matthew Donal
		CENTRAL INDEX KEY:			0001651134

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-14092
		FILM NUMBER:		22748407

	MAIL ADDRESS:	
		STREET 1:		THE BOSTON BEER COMPANY
		STREET 2:		ONE DESIGN CENTER PLACE, SUITE 850
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02210

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			BOSTON BEER CO INC
		CENTRAL INDEX KEY:			0000949870
		STANDARD INDUSTRIAL CLASSIFICATION:	MALT BEVERAGES [2082]
		IRS NUMBER:				043284048
		STATE OF INCORPORATION:			MA
		FISCAL YEAR END:			1226

	BUSINESS ADDRESS:	
		STREET 1:		ONE DESIGN CENTER PLACE
		STREET 2:		SUITE 850
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02210
		BUSINESS PHONE:		617-368-5056

	MAIL ADDRESS:	
		STREET 1:		ONE DESIGN CENTER PLACE
		STREET 2:		SUITE 850
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02210
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primarydocument.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2022-03-16</periodOfReport>

    <notSubjectToSection16>false</notSubjectToSection16>

    <issuer>
        <issuerCik>0000949870</issuerCik>
        <issuerName>BOSTON BEER CO INC</issuerName>
        <issuerTradingSymbol>SAM</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001651134</rptOwnerCik>
            <rptOwnerName>Murphy Matthew Donal</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>THE BOSTON BEER COMPANY, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>ONE DESIGN CENTER PLACE, SUITE 850</rptOwnerStreet2>
            <rptOwnerCity>BOSTON</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02210</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>false</isDirector>
            <isOfficer>true</isOfficer>
            <isTenPercentOwner>false</isTenPercentOwner>
            <isOther>false</isOther>
            <officerTitle>Chief Accounting Officer</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Class A Common</value>
            </securityTitle>
            <transactionDate>
                <value>2022-03-16</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>false</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness></transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>77.00</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>230.08</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2593.00</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">The shares were purchased pursuant to the Issuer's Employee Equity Incentive Plan on March 16, 2022, with an effective grant date of March 1, 2022. Under this plan, tenured employees may purchase
restricted shares at a discounted price. These restricted shares vest in five equal installments over a five year period, provided that the Reporting Person remains employed by the Issuer as of the applicable
vesting date. The first installment vests one year from the grant date and the final installment vests five years from the grant date. These shares have no expiration date.</footnote>
        <footnote id="F2">The shares reported include 1,538 shares of restricted stock subject to vesting conditions.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Matthew D. Murphy</signatureName>
        <signatureDate>2022-03-17</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
