Hops and temperature in brewing your ale: Cheers Physics

Hops and temperature in brewing your ale: Cheers Physics

Rik: I’m about to add the hops into the boiling wort mixture and the hops are what give your beer a lot of the flavour in terms of the bitterness and the flavours and the aroma and that’s all dependent on how long the hops are at a certain temperature so if they are at this boiling temperature for a long time you tend to get more bitterness whereas, less time, you get more of the flavours and aromas so you do it in different batches. Andy: This is a heat exchanger and on one side of the plate, the wort will go down at 100 degrees Celcius. on the other side of the plate, cold water flows through the plate. So by both of them being on opposite sides of the plate the hot wort will get cooled down by the cold water. Rik: The heat travels from Exactly, the heat will transfer effectively from the hot wort into the cold water so the hot wort will end up being cooled down to 18 degrees and the cold water will be heated up to between 50 and 60 degrees. Rik: A bit like having cold water running through your engine to keep it cool in your car Yes exactly It will also give us water available for our next brew Rik: Oh that’s heated up. that’s heated up, so actually it’s a very efficient way to heat up your water. Rik: You’re keeping that heat energy without it dissipating. Andy: Beer is quite vulnerable after we’ve stopped boiling because at that point it’s cooled down, it’s not boiled anymore and as we cool the beer, we want to get it in next door, as quick as possible and get the yeast on there as quick as possible. Because what the yeast does, once the yeast starts working, it will form a protective layer, if you like, on top of the beer, so that will help to prevent any airborne bacteria from getting into the actual beer itself and it will also create carbon dioxide, which again will help to build up a protective layer above the beer

5 thoughts on “Hops and temperature in brewing your ale: Cheers Physics”

  1. Wait, How is it possible that the cold water were heated to a temperature which was higher than the hot water due to the exchange in heat? Doesn't it contradict the Second law of thermodynamics?

  2. It still doesn't explain how the hot water were cooled down to a lower temperature than the cold water and vise versa. According to the second law of thermodynamics, a closed system will always go towards equilibrium.
    It states that if you'll place a cake in an oven for instance, the cake will be heated closer and closer to the oven's temperature and the oven will cool down because of the cake. Even if you'll keep heating the oven, the cake will never become hotter than the oven itself.

  3. But how can the circulation heat cold water to 50-60 degrees only by the exchange in heat of water which are 15-16 degrees? Where did the extra 40 degrees came from? Heat will always equalize, so even if you'll keep heating the hot water – the cold water can't be heated to a higher temperature.

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