Regardless of your Grainfather Brewing Unit, if you have a stuck mash see below:
- If liquid does not flow through the grain, then you have a 'stuck mash': To test this, stop the pump and see if the wort level on top of the grain bed drops. If the wort level does not move, then this is a 'stuck mash'.
- If the wort clears slowly, then you have a 'slow mash',
- To fix a slow or stuck mash:
- Give the grain bed a gentle stir with your paddle;
- Consider adding 1-2 handfuls of rice or oat hulls to your mash. If you don't have these on hand,. uncrushed barley malt will work, though it will add some colour and may add a small amount of fermentable to your wort;
- Be wary that a slow mash will decrease efficiency, therefore you will want to increase your mash time to be on the safe side. We recommend increasing your mash time by 1/2 hour OR do a starch test to ensure mashing has completed.
If you don't fix a stuck mash it will likely lead to a stuck sparge.
To help ensure that this does not occur in a future brew session, look to decrease your grain crush on your next batch. A stuck/slow mash is likely caused by a large portion of the grain bill being powdery or too finely crushed.