Monday, December 8, 2008

Back To the Tun

I have been away from these pages for a while but once again with good reason; I finished my brewing exams last Friday and found myself without a minute to do little else except work my day job and wearily trawl through study notes. I could have done the whole thing more intelligently. Last year I opted to cover all the really interesting brewing science aspects which I enjoyed greatly, but for the last six months I have struggled through hundreds of pages of engineering and process technology. Don't get me wrong, this stuff is essential to brewing, particularly at large volumes, but it was very mathematical, covering fluid flow, pressure changes and refrigeration cycles among many other topics. It was all a bit difficult for a lowly biochemist to cope with.

To ease the pain somewhat I dusted off my brewing equipment on Sunday and set about brewing a pale ale. I had in mind a winter type ale gently spiced perhaps but then realised that it was in fact nearly mid December and it would never be ready for Christmas and besides, my recent attempts at any beer had been awful suffering as they did with a flavour I can't account for but suspect stems from oxidation of hot cloudy wort. With this in mind I thought a straight down the line pale ale was in order to see if in fact I could brew beer at all, let alone fancy spiced ones. The recipe looked a little like this:

4.8 kgs Maris Otter
300g Crystal 60L

46g Target 9% AA 60 mins
30g Challenger 7% AA 20 mins, 10 mins
25 g Progress 5 mins, 0 mins.

Mashed at 66 C

Saf 04

OG 1.048

Some of you with a built in bittering units calculator might note that the amount of bittering hops is mental, and you would be correct. I had small amounts of hops lying around the place and just decided to throw them all in to tidy the freezer up. As I said, I am interested to see if I can brew beer at all, let alone a well crafted one, so I went a little slap dash and just used up all my spare hops. It might not be too bad; if that bloody flavour turns up again perhaps the hops will drown it out.


The Beer Nut said...

Congratulations on finishing the exams. Err, again.

Bionic Laura said...

Congratulations on finishing the exams. Enough theory, more brewing!

That recipe looks lovely. I'm fairly sure your beer will turn out great. Any of yours I've tasted are always great. Hope that off flavour doesn't appear but those hops should take care of it.

Adeptus said...

Yes, congrats on the completion! :) Are you completely finished though? You paint an image of hard work that tells me I will never be a master brewer!

You're a sensitive soul Thom. I was amazed, the other week in Dublin, that I was describing flavours from a beer we were tasting and you kept telling me that they were classic oxidation flavours :D

You might need to let that beer mature for a while to let the hops calm down a bit.

Thom said...

I'm all finished this time round. No more writing off to the college for more material for exams in June.

As for the oxidation flavours Adeptus, you noticed the blackberry like notes, and I read that these type of flavours are associated with oxidation. I couldn't taste it. The main flavour I am sensitive to is the strange flavour that none of us can quite pin down, which I am fairly sure is caused by oxidation.
It has plagued my beer recently.

Thank you for the nice comments Laura, but I have never permitted one of my oxidised beers go to trade, so to speak, so I haven't inflicted them on you.

Adeptus said...

You should, so we can all learn from the master :)

I had also picked up cardboardy notes from that beer which you did pick up, right?

Thom said...

I think we both commented on some cardboard like notes alright. I find it pretty common in home brew but never as strong as the few times I have produced it in my own beer.

Your APA and Kieron's IPA hadn't a trace of it and were very clean beers. Perhaps this is what set them apart from the other beers that evening.

Adeptus said...

Now you've tempted me to have a taste of the APA to see how clean it is, but I'm tanked up on Schloesser Alt and Hoevels after a night out at the moment (yes, German nights end early, but they begin early too). An APA would be a bridge too far right now. Maybe for breakfast... :)

Boak said...

I'm intrigued. How important is all the engineering and process stuff?

Thom said...

Boak, the truth is it is very important if you are brewing at the commercial level, but I'm not certain that a brewer would need to carry out the calculations that were inflicted upon me during exams. I fully understand the concepts but just can't apply them to the tricky mathematical queations posed.

For examample fluid travelling through a pipe and fittings drops in pressure over the distance travelled which is important in the transfer of brewing fluids and such when it comes to pumps required.

Also, cavitation is a process that damages pumps and wort. It occurs when a fluid is transfered at near its vaporisation temperature. Most typically this is wort from the kettle to the whirlpool or wort chiller. If there is a pressure drop in the pipe during the transport,which there will be as I said above, the wort will start to boil creating local areas of intense pressure as the bubblues burst which destroys pumps and ruins wort.

This is quite interesting but I don't need to know how to calculate such things. The most annoying part is at the end of the chapter when I have pulled out most of my hair attempting to figure it all out, the author states that your friendly local pump manufacturer will sort all that out for you anyway.

There are many other aspects relating to heat transfer and cooling which are equally important, but I'll spare you.