diff --git a/ircrobots/params.py b/ircrobots/params.py
index 8fd706c..3435f03 100644
--- a/ircrobots/params.py
+++ b/ircrobots/params.py
@@ -1,11 +1,15 @@
 from typing      import Optional
 from dataclasses import dataclass
 
-@dataclass
 class SASLParams(object):
-    mechanism: str
-    username:  Optional[str] = None
-    password:  Optional[str] = None
+    def __init__(self,
+            mechanism: str,
+            username:  str="",
+            password:  str=""):
+        self.mechanism = mechanism.upper()
+        self.username  = username
+        self.password  = password
+
 class SASLUserPass(SASLParams):
     def __init__(self, username: str, password: str):
         super().__init__("USERPASS", username, password)
diff --git a/ircrobots/sasl.py b/ircrobots/sasl.py
index fdd4d20..eac79f0 100644
--- a/ircrobots/sasl.py
+++ b/ircrobots/sasl.py
@@ -5,6 +5,7 @@ from irctokens   import build
 
 from .matching import Response, Numerics, ParamAny
 from .contexts import ServerContext
+from .params   import SASLParams
 
 SASL_USERPASS_MECHANISMS = [
     "SCRAM-SHA-512",
@@ -20,10 +21,20 @@ class SASLResult(Enum):
 
 class SASLError(Exception):
     pass
-class SASLUnkownMechanismError(SASLError):
+class SASLUnknownMechanismError(SASLError):
     pass
 
 class SASLContext(ServerContext):
+    async def from_params(self, params: SASLParams) -> SASLResult:
+        if params.mechanism == "USERPASS":
+            return await self.userpass(params.username, params.password)
+        elif params.mechanism == "EXTERNAL":
+            return await self.external()
+        else:
+            raise SASLUnknownMechanismError(
+                "SASLParams given with unknown mechanism "
+                f"{params.mechanism!r}")
+
     async def external(self) -> SASLResult:
         await self.server.send(build("AUTHENTICATE", ["EXTERNAL"]))
         line = await self.server.wait_for(Response("AUTHENTICATE",
@@ -34,7 +45,7 @@ class SASLContext(ServerContext):
             return SASLResult.ALREADY
         elif line.command == "908":
             available = line.params[1].split(",")
-            raise SASLUnkownMechanismError(
+            raise SASLUnknownMechanismError(
                 "Server does not support SASL EXTERNAL "
                 f"(it supports {available}")
         elif line.command == "AUTHENTICATE" and line.params[0] == "+":
@@ -53,7 +64,7 @@ class SASLContext(ServerContext):
                 if our_mech in server_mechs:
                     return our_mech
             else:
-                raise SASLUnkownMechanismError(
+                raise SASLUnknownMechanismError(
                     "No matching SASL mechanims. "
                     f"(we have: {SASL_USERPASS_MECHANISMS} "
                     f"server has: {server_mechs})")
diff --git a/ircrobots/server.py b/ircrobots/server.py
index 080853d..3431443 100644
--- a/ircrobots/server.py
+++ b/ircrobots/server.py
@@ -126,12 +126,7 @@ class Server(IServer):
             await self.send(build("CAP", ["REQ", " ".join(matches)]))
     async def _cap_ack(self, emit: Emit):
         if not self.params.sasl is None and self.cap_agreed(CAP_SASL):
-            if self.params.sasl.mechanism == "USERPASS":
-                await SASLContext(self).userpass(
-                    self.params.sasl.username or "",
-                    self.params.sasl.password or "")
-            elif self.params.sasl.mechanism == "EXTERNAL":
-                await SASLContext(self).external()
+            await SASLContext(self).from_params(self.params.sasl)
 
         for cap in (emit.tokens or []):
             if cap in self._requested_caps: