diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1420ccc..3bd96ec 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,8 @@
+# v2.1.0
+
+* Set method enforces a default TTL of `3_600` if the `expires_in` option is not provided, or is invalid.
+* Set method enforces the TTL to always be an Integer.
+
 # v2.0.0
 
 * Dropped Support for JRuby
diff --git a/lib/cache_store_redis/redis_cache_store.rb b/lib/cache_store_redis/redis_cache_store.rb
index ff4ecdf..dea9a5c 100644
--- a/lib/cache_store_redis/redis_cache_store.rb
+++ b/lib/cache_store_redis/redis_cache_store.rb
@@ -1,5 +1,8 @@
 # This class is used to implement a redis cache store.
 class RedisCacheStore
+  # Default expiry time if not provided. (1 hour)
+  DEFAULT_TTL = 3_600
+
   def initialize(namespace = nil, config = nil)
     @connection_pool = RedisConnectionPool.new(config)
 
@@ -59,7 +62,7 @@ def with_client
   # @param key [String] This is the unique key to reference the value being set within this cache store.
   # @param value [Object] This is the value to set within this cache store.
   # @param expires_in [Integer] This is the number of seconds from the current time that this value should expire.
-  def set(key, value, expires_in = 3_600)
+  def set(key, value, expires_in = DEFAULT_TTL)
     k = build_key(key)
 
     v = if value.nil? || (value.is_a?(String) && value.strip.empty?)
@@ -68,11 +71,14 @@ def set(key, value, expires_in = 3_600)
       serialize(value)
     end
 
+    expiry_int = Integer(expires_in)
+    expire_value = expiry_int.positive? ? expiry_int : DEFAULT_TTL
+
     with_client do |client|
       client.multi do
         client.set(k, v)
 
-        client.expire(k, expires_in) if expires_in.positive?
+        client.expire(k, expire_value)
       end
     end
   end
diff --git a/lib/cache_store_redis/version.rb b/lib/cache_store_redis/version.rb
index 63f36ff..a293ed2 100644
--- a/lib/cache_store_redis/version.rb
+++ b/lib/cache_store_redis/version.rb
@@ -1,3 +1,3 @@
 module CacheStoreRedis
-  VERSION = '2.0.0'
+  VERSION = '2.1.0'
 end
diff --git a/spec/cache_store_redis_spec.rb b/spec/cache_store_redis_spec.rb
index cf60f1a..27fdafa 100644
--- a/spec/cache_store_redis_spec.rb
+++ b/spec/cache_store_redis_spec.rb
@@ -9,6 +9,35 @@
   end
 
   describe "#set" do
+    context 'expires_in' do
+      let(:key) { SecureRandom.uuid }
+      let(:value) { 'SomeValue' }
+
+      it 'will always set a default TTL if one is not provided' do
+        expect_any_instance_of(Redis).to receive(:set).with("test:#{key}", "\"#{value}\"")
+        expect_any_instance_of(Redis).to receive(:expire).with("test:#{key}", 3_600)
+        @cache_store.set(key, value)
+      end
+
+      it 'will always set a default TTL if an invalid one is provided' do
+        expect_any_instance_of(Redis).to receive(:set).with("test:#{key}", "\"#{value}\"")
+        expect_any_instance_of(Redis).to receive(:expire).with("test:#{key}", 3_600)
+        @cache_store.set(key, value, -200)
+      end
+
+      it 'will always set a default TTL if an invalid one is provided' do
+        expect_any_instance_of(Redis).to receive(:set).with("test:#{key}", "\"#{value}\"")
+        expect_any_instance_of(Redis).to receive(:expire).with("test:#{key}", 3_600)
+        @cache_store.set(key, value, 0.456)
+      end
+
+      it 'will always force the TTL to be an integer' do
+        expect_any_instance_of(Redis).to receive(:set).with("test:#{key}", "\"#{value}\"")
+        expect_any_instance_of(Redis).to receive(:expire).with("test:#{key}", 20)
+        @cache_store.set(key, value, 20.123)
+      end
+    end
+
     it 'should add a string to the cache store and retrieve it' do
       key = SecureRandom.uuid
       value = 'value123'