Liquibase spring bean "log" property

I've currently managed to configure my Spring application to work with liquibase in a way that it runs the update command whenever I start the application. The problem is that I'd like to be able to see the output log from liquibase in a different file in order to be able to clearly see what has happened to my database, without having to search the entire startup log that can get really big in size. Could you explain a bit how the "log" property of the spring bean works? 

Currently I have in my log4j.properties file a line like this:
      log4j.appender.liquibase=org.apache.log4j.RollingFileAppender
and I would like to use this as my default liquibase logger.

Any help or insight on this matter?

Thanks in advance.