diff --git a/frame/evm/src/lib.rs b/frame/evm/src/lib.rs
index 6c1f52a642c03..48b54a8c8677e 100644
--- a/frame/evm/src/lib.rs
+++ b/frame/evm/src/lib.rs
@@ -165,7 +165,7 @@ decl_storage! {
 	trait Store for Module<T: Trait> as Example {
 		Accounts get(fn accounts) config(): map H160 => Account;
 		AccountCodes: map H160 => Vec<u8>;
-		AccountStorages: double_map H160, blake2_256(H256) => H256;
+		AccountStorages: double_map H160, H256 => H256;
 	}
 }
 
diff --git a/frame/generic-asset/src/lib.rs b/frame/generic-asset/src/lib.rs
index ceadd937fc052..0a0209b20f175 100644
--- a/frame/generic-asset/src/lib.rs
+++ b/frame/generic-asset/src/lib.rs
@@ -492,10 +492,10 @@ decl_storage! {
 		}): map T::AssetId => T::Balance;
 
 		/// The free balance of a given asset under an account.
-		pub FreeBalance: double_map T::AssetId, twox_128(T::AccountId) => T::Balance;
+		pub FreeBalance: double_map T::AssetId, hasher(twox_128) T::AccountId => T::Balance;
 
 		/// The reserved balance of a given asset under an account.
-		pub ReservedBalance: double_map T::AssetId, twox_128(T::AccountId) => T::Balance;
+		pub ReservedBalance: double_map T::AssetId, hasher(twox_128) T::AccountId => T::Balance;
 
 		/// Next available ID for user-created asset.
 		pub NextAssetId get(fn next_asset_id) config(): T::AssetId;
diff --git a/frame/im-online/src/lib.rs b/frame/im-online/src/lib.rs
index 64cd9fae6f420..71406f9b375e2 100644
--- a/frame/im-online/src/lib.rs
+++ b/frame/im-online/src/lib.rs
@@ -229,13 +229,12 @@ decl_storage! {
 
 		/// For each session index, we keep a mapping of `AuthIndex`
 		/// to `offchain::OpaqueNetworkState`.
-		ReceivedHeartbeats get(fn received_heartbeats): double_map SessionIndex,
-			blake2_256(AuthIndex) => Option<Vec<u8>>;
+		ReceivedHeartbeats get(fn received_heartbeats): double_map SessionIndex, AuthIndex
+			=> Option<Vec<u8>>;
 
 		/// For each session index, we keep a mapping of `T::ValidatorId` to the
 		/// number of blocks authored by the given authority.
-		AuthoredBlocks get(fn authored_blocks): double_map SessionIndex,
-			blake2_256(T::ValidatorId) => u32;
+		AuthoredBlocks get(fn authored_blocks): double_map SessionIndex, T::ValidatorId => u32;
 	}
 	add_extra_genesis {
 		config(keys): Vec<T::AuthorityId>;
diff --git a/frame/offences/src/lib.rs b/frame/offences/src/lib.rs
index f0a2cb04ee51e..310c018d76134 100644
--- a/frame/offences/src/lib.rs
+++ b/frame/offences/src/lib.rs
@@ -57,7 +57,7 @@ decl_storage! {
 		Reports get(fn reports): map ReportIdOf<T> => Option<OffenceDetails<T::AccountId, T::IdentificationTuple>>;
 
 		/// A vector of reports of the same kind that happened at the same time slot.
-		ConcurrentReportsIndex: double_map Kind, blake2_256(OpaqueTimeSlot) => Vec<ReportIdOf<T>>;
+		ConcurrentReportsIndex: double_map Kind, OpaqueTimeSlot => Vec<ReportIdOf<T>>;
 
 		/// Enumerates all reports of a kind along with the time they happened.
 		///
diff --git a/frame/session/src/lib.rs b/frame/session/src/lib.rs
index 2c5668f6fa9f2..2200221af42fe 100644
--- a/frame/session/src/lib.rs
+++ b/frame/session/src/lib.rs
@@ -398,13 +398,15 @@ decl_storage! {
 		///
 		/// The first key is always `DEDUP_KEY_PREFIX` to have all the data in the same branch of
 		/// the trie. Having all data in the same branch should prevent slowing down other queries.
-		NextKeys: double_map hasher(twox_64_concat) Vec<u8>, blake2_256(T::ValidatorId) => Option<T::Keys>;
+		NextKeys: double_map hasher(twox_64_concat) Vec<u8>, hasher(blake2_256) T::ValidatorId
+			=> Option<T::Keys>;
 
 		/// The owner of a key. The second key is the `KeyTypeId` + the encoded key.
 		///
 		/// The first key is always `DEDUP_KEY_PREFIX` to have all the data in the same branch of
 		/// the trie. Having all data in the same branch should prevent slowing down other queries.
-		KeyOwner: double_map hasher(twox_64_concat) Vec<u8>, blake2_256((KeyTypeId, Vec<u8>)) => Option<T::ValidatorId>;
+		KeyOwner: double_map hasher(twox_64_concat) Vec<u8>, hasher(blake2_256) (KeyTypeId, Vec<u8>)
+			=> Option<T::ValidatorId>;
 	}
 	add_extra_genesis {
 		config(keys): Vec<(T::ValidatorId, T::Keys)>;
diff --git a/frame/staking/src/lib.rs b/frame/staking/src/lib.rs
index deb451f35c832..1331f869b705a 100644
--- a/frame/staking/src/lib.rs
+++ b/frame/staking/src/lib.rs
@@ -738,11 +738,11 @@ decl_storage! {
 		/// All slashing events on validators, mapped by era to the highest slash proportion
 		/// and slash value of the era.
 		ValidatorSlashInEra:
-			double_map EraIndex, twox_128(T::AccountId) => Option<(Perbill, BalanceOf<T>)>;
+			double_map EraIndex, hasher(twox_128) T::AccountId => Option<(Perbill, BalanceOf<T>)>;
 
 		/// All slashing events on nominators, mapped by era to the highest slash value of the era.
 		NominatorSlashInEra:
-			double_map EraIndex, twox_128(T::AccountId) => Option<BalanceOf<T>>;
+			double_map EraIndex, hasher(twox_128) T::AccountId => Option<BalanceOf<T>>;
 
 		/// Slashing spans for stash accounts.
 		SlashingSpans: map T::AccountId => Option<slashing::SlashingSpans>;
diff --git a/frame/support/procedural/src/lib.rs b/frame/support/procedural/src/lib.rs
index faac4baec39f8..7c27bc2a04dcb 100644
--- a/frame/support/procedural/src/lib.rs
+++ b/frame/support/procedural/src/lib.rs
@@ -117,7 +117,7 @@ use proc_macro::TokenStream;
 ///   Twox128(module_prefix) ++ Twox128(head_prefix)
 ///   ```
 ///
-/// * Double map: `Foo: double_map hasher($hash1) u32, $hash2(u32) => u32`: Implements the
+/// * Double map: `Foo: double_map hasher($hash1) u32, hasher($hash2) u32 => u32`: Implements the
 ///   [`StorageDoubleMap`](../frame_support/storage/trait.StorageDoubleMap.html) trait using the
 ///   [`StorageDoubleMap generator`](../frame_support/storage/generator/trait.StorageDoubleMap.html).
 ///   And [`StoragePrefixedMap`](../frame_support/storage/trait.StoragePrefixedMap.html).
@@ -126,10 +126,8 @@ use proc_macro::TokenStream;
 ///   [`Hashable`](../frame_support/trait.Hashable.html) trait. They must be choosen with care, see
 ///   generator documentation.
 ///
-///   `hasher($hash)` is optional and its default is `blake2_256`.
-///
-///   `hasher($hash)` is optional and its default is `blake2_256`. One should use another hasher
-///   with care, see generator documentation.
+///   `hasher($hash1)` and `hasher($hash2) are optional and default to `blake2_256`.
+///   One should use another hasher with care, see generator documentation.
 ///
 ///   If the first key is untrusted, a cryptographic `hasher` such as `blake2_256` must be used.
 ///   Otherwise, other values of all storage items can be compromised.
diff --git a/frame/support/procedural/src/storage/parse.rs b/frame/support/procedural/src/storage/parse.rs
index a2d3c67dd2f8e..5d91fbcc0e912 100644
--- a/frame/support/procedural/src/storage/parse.rs
+++ b/frame/support/procedural/src/storage/parse.rs
@@ -167,11 +167,11 @@ struct DeclStorageLinkedMap {
 #[derive(Parse, ToTokens, Debug)]
 struct DeclStorageDoubleMap {
 	pub map_keyword: keyword::double_map,
-	pub hasher: ext::Opt<SetHasher>,
+	pub hasher1: ext::Opt<SetHasher>,
 	pub key1: syn::Type,
 	pub comma_keyword: Token![,],
-	pub key2_hasher: Hasher,
-	pub key2: ext::Parens<syn::Type>,
+	pub hasher2: ext::Opt<SetHasher>,
+	pub key2: syn::Type,
 	pub ass_keyword: Token![=>],
 	pub value: syn::Type,
 }
@@ -380,11 +380,12 @@ fn parse_storage_line_defs(
 			),
 			DeclStorageType::DoubleMap(map) => super::StorageLineTypeDef::DoubleMap(
 				super::DoubleMapDef {
-					hasher1: map.hasher.inner.map(Into::into)
+					hasher1: map.hasher1.inner.map(Into::into)
+						.unwrap_or(super::HasherKind::Blake2_256),
+					hasher2: map.hasher2.inner.map(Into::into)
 						.unwrap_or(super::HasherKind::Blake2_256),
-					hasher2: map.key2_hasher.into(),
 					key1: map.key1,
-					key2: map.key2.content,
+					key2: map.key2,
 					value: map.value,
 				}
 			),
diff --git a/frame/support/src/lib.rs b/frame/support/src/lib.rs
index af6eea9c73fb3..bfee0a1ccb8b4 100644
--- a/frame/support/src/lib.rs
+++ b/frame/support/src/lib.rs
@@ -236,12 +236,12 @@ mod tests {
 			pub GetterNoFnKeyword get(no_fn): Option<u32>;
 
 			pub DataDM config(test_config) build(|_| vec![(15u32, 16u32, 42u64)]):
-				double_map hasher(twox_64_concat) u32, blake2_256(u32) => u64;
+				double_map hasher(twox_64_concat) u32, hasher(blake2_256) u32 => u64;
 			pub GenericDataDM:
-				double_map T::BlockNumber, twox_128(T::BlockNumber) => T::BlockNumber;
+				double_map T::BlockNumber, hasher(twox_128) T::BlockNumber => T::BlockNumber;
 			pub GenericData2DM:
-				double_map T::BlockNumber, twox_256(T::BlockNumber) => Option<T::BlockNumber>;
-			pub AppendableDM: double_map u32, blake2_256(T::BlockNumber) => Vec<u32>;
+				double_map T::BlockNumber, hasher(twox_256) T::BlockNumber => Option<T::BlockNumber>;
+			pub AppendableDM: double_map u32, T::BlockNumber => Vec<u32>;
 		}
 	}
 
diff --git a/frame/support/test/tests/decl_storage.rs b/frame/support/test/tests/decl_storage.rs
index b0974fcb8292a..15a0807fa5701 100644
--- a/frame/support/test/tests/decl_storage.rs
+++ b/frame/support/test/tests/decl_storage.rs
@@ -562,9 +562,9 @@ mod test_append_and_len {
 			MapVecWithDefault: map u32 => Vec<u32> = vec![6, 9];
 			OptionMapVec: map u32 => Option<Vec<u32>>;
 
-			DoubleMapVec: double_map u32, blake2_256(u32) => Vec<u32>;
-			DoubleMapVecWithDefault: double_map u32, blake2_256(u32) => Vec<u32> = vec![6, 9];
-			OptionDoubleMapVec: double_map u32, blake2_256(u32) => Option<Vec<u32>>;
+			DoubleMapVec: double_map u32, u32 => Vec<u32>;
+			DoubleMapVecWithDefault: double_map u32, u32 => Vec<u32> = vec![6, 9];
+			OptionDoubleMapVec: double_map u32, u32 => Option<Vec<u32>>;
 
 			LinkedMapVec: linked_map u32 => Vec<u32>;
 			LinkedMapVecWithDefault: linked_map u32 => Vec<u32> = vec![6, 9];
diff --git a/frame/support/test/tests/final_keys.rs b/frame/support/test/tests/final_keys.rs
index 71e13f7ced561..9f1b379e2544d 100644
--- a/frame/support/test/tests/final_keys.rs
+++ b/frame/support/test/tests/final_keys.rs
@@ -41,12 +41,12 @@ mod no_instance {
 			pub LinkedMap: linked_map u32 => u32;
 			pub LinkedMap2: linked_map hasher(twox_128) u32 => u32;
 
-			pub DoubleMap: double_map u32, blake2_256(u32) => u32;
-			pub DoubleMap2: double_map hasher(twox_128) u32, blake2_128(u32) => u32;
+			pub DoubleMap: double_map u32, u32 => u32;
+			pub DoubleMap2: double_map hasher(twox_128) u32, hasher(blake2_128) u32 => u32;
 
 			pub TestGenericValue get(fn test_generic_value) config(): Option<T::BlockNumber>;
 			pub TestGenericDoubleMap get(fn foo2) config(test_generic_double_map):
-				double_map u32, blake2_256(T::BlockNumber) => Option<u32>;
+				double_map u32, T::BlockNumber => Option<u32>;
 		}
 	}
 }
@@ -71,12 +71,12 @@ mod instance {
 			pub LinkedMap: linked_map u32 => u32;
 			pub LinkedMap2: linked_map hasher(twox_128) u32 => u32;
 
-			pub DoubleMap: double_map u32, blake2_256(u32) => u32;
-			pub DoubleMap2: double_map hasher(twox_128) u32, blake2_128(u32) => u32;
+			pub DoubleMap: double_map u32, u32 => u32;
+			pub DoubleMap2: double_map hasher(twox_128) u32, hasher(blake2_128) u32 => u32;
 
 			pub TestGenericValue get(fn test_generic_value) config(): Option<T::BlockNumber>;
 			pub TestGenericDoubleMap get(fn foo2) config(test_generic_double_map):
-				double_map u32, blake2_256(T::BlockNumber) => Option<u32>;
+				double_map u32, T::BlockNumber => Option<u32>;
 		}
 		add_extra_genesis {
 			// See `decl_storage` limitation.
diff --git a/frame/support/test/tests/genesisconfig.rs b/frame/support/test/tests/genesisconfig.rs
index 04525aa142d97..dee7aefe0aaa3 100644
--- a/frame/support/test/tests/genesisconfig.rs
+++ b/frame/support/test/tests/genesisconfig.rs
@@ -25,7 +25,7 @@ frame_support::decl_module! {
 
 frame_support::decl_storage! {
 	trait Store for Module<T: Trait> as Example {
-		pub AppendableDM config(t): double_map u32, blake2_256(T::BlockNumber) => Vec<u32>;
+		pub AppendableDM config(t): double_map u32, T::BlockNumber => Vec<u32>;
 	}
 }
 
diff --git a/frame/support/test/tests/instance.rs b/frame/support/test/tests/instance.rs
index e4b707c1f170c..879ef4fa684d2 100644
--- a/frame/support/test/tests/instance.rs
+++ b/frame/support/test/tests/instance.rs
@@ -138,7 +138,7 @@ mod module2 {
 			pub Value config(value): T::Amount;
 			pub Map config(map): map u64 => u64;
 			pub LinkedMap config(linked_map): linked_map u64 => Vec<u8>;
-			pub DoubleMap config(double_map): double_map u64, blake2_256(u64) => u64;
+			pub DoubleMap config(double_map): double_map u64, u64 => u64;
 		}
 	}
 
diff --git a/frame/utility/src/lib.rs b/frame/utility/src/lib.rs
index 8103939a5c6a3..97c8f668a6e5c 100644
--- a/frame/utility/src/lib.rs
+++ b/frame/utility/src/lib.rs
@@ -127,7 +127,8 @@ pub struct Multisig<BlockNumber, Balance, AccountId> {
 decl_storage! {
 	trait Store for Module<T: Trait> as Utility {
 		/// The set of open multisig operations.
-		pub Multisigs: double_map hasher(twox_64_concat) T::AccountId, blake2_128_concat([u8; 32])
+		pub Multisigs: double_map
+			hasher(twox_64_concat) T::AccountId, hasher(blake2_128_concat) [u8; 32]
 			=> Option<Multisig<T::BlockNumber, BalanceOf<T>, T::AccountId>>;
 	}
 }
diff --git a/utils/frame/rpc/support/src/lib.rs b/utils/frame/rpc/support/src/lib.rs
index ba467abd924c8..1e29c4e91b495 100644
--- a/utils/frame/rpc/support/src/lib.rs
+++ b/utils/frame/rpc/support/src/lib.rs
@@ -67,7 +67,7 @@ use sc_rpc_api::state::StateClient;
 ///         pub LastActionId: u64;
 ///         pub Voxels: map Loc => Block;
 ///         pub Actions: linked_map u64 => Loc;
-///         pub Prefab: double_map u128, blake2_256((i8, i8, i8)) => Block;
+///         pub Prefab: double_map u128, (i8, i8, i8) => Block;
 ///     }
 /// }
 ///