diff --git a/gnosis/eth/utils.py b/gnosis/eth/utils.py
index 2193c18b2..c6a691962 100644
--- a/gnosis/eth/utils.py
+++ b/gnosis/eth/utils.py
@@ -22,7 +22,7 @@ def get_empty_tx_params() -> TxParams:
     }
 
 
-@lru_cache(maxsize=os.environ.get("CACHE_KECCAK", None))
+@lru_cache(maxsize=int(os.getenv("CACHE_KECCAK", 512)))
 def _keccak_256(value: bytes) -> bytes:
     return keccak_256(value)
 
@@ -87,7 +87,7 @@ def _build_checksum_address(
     )
 
 
-@lru_cache(maxsize=os.environ.get("CACHE_CHECKSUM_ADDRESS", None))
+@lru_cache(maxsize=int(os.getenv("CACHE_CHECKSUM_ADDRESS", 1_000_000_000)))
 def _fast_to_checksum_address(address: HexAddress):
     address_hash = fast_keccak_hex(address.encode())
     return _build_checksum_address(address, address_hash)