Irish moss (Chondrus crispus) – an edible seaweed that grows along the rocky Atlantic coasts of Europe and North America. It comes in both dried, tea-like leaves and concentrated powder.

  • A majority of the Irish moss plant consists of carrageenan, which is key to clarify beer during the boil. Carrageenan has a negative electrostatic charge. Protein clumps from the boiling wort’s hot break are positively charged. Because of the attraction between proteins and carrageenan, larger clumps of hot break material form, making them more likely to precipitate out of suspension in a faster manner. Ultimately the clumps will not make it into the fermenter.
  • Generally all Irish moss products are rehydrated and added within the last 20 minutes of the boil.
  • Carefully measure recommended quantities in relation to boil volume.
    • Adding too much Irish moss negatively affects small proteins responsible for head retention.
    • Too much finings may also reduce Free Amino Acid levels that are crucial in healthy yeast growth and clean fermentation.