During one of my recent brew days whilst using the Grainfather, I encountered a stuck sparge. Although a rare occasion if everything is done correctly, it happens – here are some tips on overcoming the problem and preventing it from happening in the future!
What is a stuck sparge?
A stuck sparge is where the sparge water cannot flow through the grain bed normally, a stuck sparge can also occur when you are recirculating the wort during the mash and the wort builds up at the top of the grain bed.
It is much more common when using malts with high protein such as wheat malt, however, it can happen during any brew day with any recipe!
How can you fix a stuck sparge?
Add more water
If you are still at the mash stage and are facing the problem of the recirculated wort collecting at the top and not making it through, you can simply add some more water at the appropriate temperature. After adding more water, make sure to give the mash a good stir with a mash paddle. The cause of the wort not being able to recirculate during the mash is likely to be not enough water has been added originally.
If you are sparging, you can do the same but not stir the grain bed, adding lots of water at once can cause the grains to float, helping to free the blockage. Make sure there is no Perforated Plate touching the grains when doing this.
Slice holes in the grain bed
If you can fix the stuck sparge without disturbing the grain bed then that would be the preferred option, but if there is no other choice you can slice holes using your mash paddle.
Try to avoid twisting the paddle or stirring as this will cause the grain to be released into the wort but if the above does not break it then this can be done as a last resort.
How can you avoid a stuck sparge?
There are a few things you can be doing to prevent a stuck sparge from happening. By following these tips you will reduce the chances of this happening to you during a brew day.
A mash out is where you raise the temperature of your mash to around 75°C for around 10 minutes after the usual 60-minute mash. This halts the enzymes which are busy converting starches into sugars. If you are using the Grainfather, their recipe generator app will automatically add the mash-out stage for you.
The sugars become more soluble, this helps to maintain a wort that is less sticky and thinner.
It’s recommended to do a mash-out on most brews however it’s especially important when there is a higher risk of a stuck sparge, for example when there is a high percentage of wheat malt.
Position of Perforated Plate
If you are sparging using a Perforated Plate, (this is the part supplied with the Grainfather which sits above the grain bed to evenly distribute the sparge water or recirculated wort) then ensure you do not press it down so that it is putting pressure on the grain bed. Instead, try and ensure there is a few centimetres gap, this will allow the sparge water or recirculated wort to collect underneath the plate making it easier to travel through the grain bed.
Ensuring that you always add the grains slowly and thoroughly soak them by folding them into the water with the mash paddle will help to avoid a stuck sparge.
Correct Grain Crush
When crushing your grain, if the bulk of the husks are damaged, this can cause the grain bed to not form correctly and consequently contribute to a stuck sparge.
Adding around 200g of rice hulls for a 23L batch can help separate the grains and allow the sparge water or recirculated wort a clearer path to run through the grains and properly rinse the sugars from the grain bed.