Let me first say that I am not an expert on CA tenancy laws, nor do I know what your lease says. What I can say comes from my experience as in Texas as an apartment dweller and some general contract rules.
Most leases are drafted by an industry group (of landlord businesses) or at least have been constructed with legal assistance to protect the landlord's interests. There are likely clauses buried in the lease that allow them to classify what you are doing as "dangerous" to other tenants or the building, so they could tell you to stop engaging in a particular activity upon threat of eviction. So, fighting with your landlord over this puts you at a severe risk (even if you don't care about getting kicked out of this rental, other landlords will be loathe to allow you as a tenant knowing you were evicted.)
On the otherhand, what you are doing is really little more than boiling food and storing it in plastic/glass containers, and surely that would be permitted under your lease. However, there may be general issues with how you brew that are forbidden under the lease. For example, if you are brewing outdoors on a fryer, your lease may forbid you to operate a heat source on your balcony/patio (if that applies). Your lease may forbid you from building/using homemade electrical devices, etc.
Before you tell your landlord to shove it, keep in mind that your lease can be used -- very easily -- by your landlord to evict you. If I were in your shoes, I'd ask him to discuss the matter with you further to give you an opportunity to provide more information on your processes and try to work out some compromise to keep both sides happy.