<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2024-09-20</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000095953</issuerCik>
        <issuerName>ASCENT INDUSTRIES CO.</issuerName>
        <issuerTradingSymbol>ACNT</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0002012178</rptOwnerCik>
            <rptOwnerName>Kitchen John Bryan</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>20 N. MARTINGALE RD</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 430</rptOwnerStreet2>
            <rptOwnerCity>SCHAUMBURG</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60173</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Executive Officer</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2024-09-20</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>11170</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>8.61</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>50841</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">The reported price in column 4 is a weighted average purchase price. These shares were purchased in multiple transactions at prices ranging from $8.59 to $8.86 per share.
The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchanges Commission, upon request, full
information regarding the number of shares purchased at each separate price within the range set forth within this footnote.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>John Bryan Kitchen</signatureName>
        <signatureDate>2024-09-24</signatureDate>
    </ownerSignature>
</ownershipDocument>
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X0508
4
2024-09-20
0
0000095953
ASCENT INDUSTRIES CO.
ACNT
0002012178
Kitchen John Bryan
20 N. MARTINGALE RD
SUITE 430
SCHAUMBURG
IL
60173
1
1
0
0
Chief Executive Officer
0
Common Stock
2024-09-20
4
P
0
11170
8.61
A
50841
D
The reported price in column 4 is a weighted average purchase price. These shares were purchased in multiple transactions at prices ranging from $8.59 to $8.86 per share.
The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchanges Commission, upon request, full
information regarding the number of shares purchased at each separate price within the range set forth within this footnote.
John Bryan Kitchen
2024-09-24