如何在启用后禁用CURLOPT_ENCODING？

Take a cURL handle:

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, "example.com");

// Add request headers to curl_getinfo()
curl_setopt($ch, CURLINFO_HEADER_OUT, true); 

// Enable compression (usually gzip)
curl_setopt($ch, CURLOPT_ENCODING, '');

curl_exec($ch);

Now I would like to reuse this cURL handle to make another request. (I think that is common and recommended.)

But I want this second request to be made without an Accept-Encoding header. How can I undo the effect of curl_setopt($ch, CURLOPT_ENCODING, '')?

I tried setting it to null and false but they had no effect.