Thursday, April 26, 2007

Time to replace the fermentation vessels

The ESB had a slight bacterial infection. It had lost all of its malt flavours and there were next to no hop aroma, making it monotonous, grassy and slightly dry. It also had an astringent yeast-like character, but I don't think that has got anything to do with the yeast at all. The infection started out as just a hint of altered flavours, but has over the last couple of weeks become much more evident. It is without a doubt an infection. At this rate I pick up an infection every 35 batches. This is the second time it has happened.

I judged a couple of flights at this year's Norwegian Homebrewing Championships and noticed that a couple of the entries had the same defect. At that time I suspected that it was a fermentation issue, most likely caused by autolysis or bad yeast health. I'm now confident that it is indeed a small bacterial infection, or the beginning of one.

There's nothing that one can do about a bacterial infection other that to discard the beer. I'm sure you could drink it, but life's too short. Unlike other defects there's actually no steps you can take to improve the beers drinkablity. So the ESB is going to make do as fertilizer in the garden.

Interestingly the three beers I have brewed after the infected one do not have any signs of infection. This has led me to suspect that it is the fermentation vessel that has caused the infection. It could of course also have been a mistake made by yours truly.

Plastic has the unfortunate characteristic that it easily get scratched over time, and those scratches can harbour bacteria. I have four plastic fermentation vessels and I do think I used all four on those last four beers, so it seems that none of the other beers touched the infected one.

Anyway, my plastic fermentation vessels are five years old. I should have replaced them earlier, but they have now for sure reached their end of duty. They were thrown out yesterday together with the plastic tubing.

New fermenters will have to be bought ASAP as I have more work to do before the summer.

Thursday, April 19, 2007

How to clean a picnic faucet

Did you know that you can take the picnic faucet apart? I didn't. It came as a surprise to me when I saw Richard rip one apart and explain that that would expose all the surface that the beer touches. It consists of two individual pieces. That's great as I had suspected that just running cleaner and sanitizer through wouldn't be enough to clean it.

I am a bit scared of what I'll find when I open one, especially the older ones. I can't say I've had any off-flavours when using them, but I fear the worst. In any case they can all expect thorough cleaning before being used the next time.

Monday, April 16, 2007

Brew #47: Imperial Porter

Too many of my recent brews have been brownish in colour, so it was now time to make something really dark. The intention was to make a normal strength robust porter at around 6.0% abv, but the mash efficiency was pretty good for a dark beer and it came out as an imperial porter. Things could have been worse.

I have had terrible mash efficiencies when making dark beers earlier. Fortunately things went better this time.

An extraordinarily fine crush made by Frode's Crankandstein (or is it Crankenstein monster?) must have contributed somewhat, but not enough to replace the Barley Crusher though. I noticed a lot of dry grain balls in the mash as I doughed in, but a few minutes of stirring made them go way. So it was clear that the crush was much finer than what I have had earlier. There were no hints of any run-off problems, so the crush is fine. I also tried to sparge a little slower than at full speed making it more likely to extract more sugars. Each sparge took about 10 minutes, which is still a reasonably short time. I'll consider reducing the gap my own Barley Crusher for the next brew. It is currently set to the default.

The water in Oslo is extremely soft, very much like the water in Plzen, something that makes it perfect for light beers like pilsener. At the same time this makes it harder to make dark beers. Soft water is really the perfect brew water as it is a lot easier to add minerals than it is to take them out. So to emulate the water of other famous brewing cities one can just add minerals.

I made a porter with 500 grams of chocolate malt and black malt about a year and a half ago, which turned into something very harsh and astringent. I blame the pH of the water. A low pH means a lower mash efficiency and extraction of undesired characteristics like tannins. This time I added 2.5 ts calcium carbonate and 2 ts of 5.2 powder. The recipe also use dehusked dark malts, which should keep the sharp edges out of the beer. I also added the dark malts 45 minutes into the mash, giving the base malt a better chance of converting itself before the pH gets lowered by the dark malts.

The batch was brewed 2007-04-16.

Imperial Porter
All grain, batch sparge
80 EBC (Black)
40 IBU
5000g Pale malt
1000g Munich malt
500g Amber malt
400g Crystal malt, 300 EBC
400g Crystal malt, 130 EBC
250g Carafa I, debittered chocolate malt
250g Carafa II, debittered black malt
68C, 60 min
76C, 10 min (mashout)
72% efficiency
30g Warrior pellets, 13.8%, 60 min
20g Warrior pellets, 13.8%, 10 min
Nottingham, 2 packs, dry yeast, best before date 2007-01-15 and 2007-12-01.
90 min
OG: 1.068 FG: 1.017 (estimated) abv: 6.7%

Wednesday, April 11, 2007

Brew #46: Weissbier

It has been a really long time since I brewed a German weissbier. Too long, in fact two years ago. That's even before I started kegging my beers. Heck, it is one of my favourite beer styles, and perfect for the upcoming warm season.

The recipe is straightforward. I did an acid rest this time as it will improve the clove flavours. I used the Wyeast 3068 yeast, which in my opinion is the best weissbier yeast that there is. It'll generate little banana, but that depends a little on the fermentation temperature.

The wheat malt percentage is quite high at 59%, which is quite high, but still quite common. Wheat malt can be notoriously difficult to sparge as it easily clogs up the mash. I have been impressed by the Bazooka screen in my mash tun as it seems to work really well even with malt bills that are hard to sparge. I tried to batch sparge as quickly as possible and opened the ball valve fully from the start. The mash soon compacted on itself and the grains moved about 3 cm from the walls towards the Bazooka. Alright, a stuck sparge, but it was really easy to get the flow going again. Cutting into the grains with a knife released the vaccuum and the sparge continued at a nice rate. I can very much recommend the Bazooka screen. It's pretty impressive. It is also quite cool that a stuck mash is nothing to be afraid of as one can just cut or stir the mash to start the sparge again.

I decided to add a little melanoidin malt to add some complexity and fill out the body.

The batch was brewed 2007-04-11.

All grain, batch sparge
9 EBC (Golden)
14 IBU
3500g Wheat malt
2500g Pilsener malt
200g Melanoidin malt
44C, 15 min (acid rest)
64C, 60 min
76C, 10 min (mashout)
73% efficiency
50g Tettnanger pellets, 2.7%, 60 min
20g Tettnanger pellets, 2.7%, 10 min
Wyeast 3068 Weihenstephan Weizen Yeast, production date 2007-01-15, 1 liter starter
90 min
OG: 1.055 FG: 1.013 (estimated) abv: 5.5%