Short answer. You owe the monetary value of the rice at the time the loan was perfected. Under Article 1955, if you borrowed a fungible thing other than money, you normally owe back the same kind, quantity, and quality — but when delivery of the same kind becomes impossible, you pay its value at the time of the loan's perfection instead.
What the law says
If what was loaned is a fungible thing other than money, the debtor owes another thing of the same kind, quantity and quality, even if it should change in value. In case it is impossible to deliver the same kind, its value at the time of the perfection of the loan shall be paid.
Civil Code, Article 1955 — Obligation of the Money/Fungible Borrower. Read the full provision →
Fungible things and the simple mutuum
A loan of fungible goods — rice, grain, cooking oil, or similar commodities — is a simple loan or mutuum under the Civil Code. What makes goods fungible is that individual units are interchangeable with others of the same kind: a sack of jasmine rice is equivalent to any other sack of jasmine rice of the same grade. When you borrow fungibles, you do not owe the exact same sacks back — you owe the same amount of the same kind and quality. Article 1955 also adds that you owe this even if it should change in value between the loan and repayment — market fluctuations do not shift the obligation.
When the same kind can no longer be delivered
Article 1955 provides a fallback for genuine impossibility: if it is impossible to deliver the same kind, its value at the time of the perfection of the loan shall be paid. The reference point for valuation is the moment the loan agreement was finalized — not the current market price and not the price at the time repayment falls due. This protects both parties: the lender is made whole at the value agreed upon, and the borrower is not exposed to whatever the market price might be today for a product that no longer exists in the form originally borrowed.
What counts as genuine impossibility
The article applies when delivery of the same kind is impossible — meaning the variety no longer exists, was declared unfit for commerce, or is otherwise entirely unavailable. Simple difficulty in sourcing the variety, or the fact that it is now rare and expensive, is not the same as impossibility. If the variety can still be found and purchased, even at a higher price than when you borrowed it, you remain obligated to return the same kind, quantity, and quality. The impossibility must be actual, not merely inconvenient.
The valuation date matters
Anchoring the valuation to the time of the loan's perfection is significant. If you borrowed rice when it was abundant and inexpensive, and the variety has since become unobtainable for whatever reason, the lender receives what the rice was worth when the loan was made — not an inflated price reflecting its rarity today. Conversely, the lender is not left with less than they originally extended. Keeping a record of the agreed value at the time of the loan, or at least the market price on that date, is useful for any future dispute about what the monetary equivalent should be.