Friday 30 September 2016

The first stock pale ale in 70 years, again.

Obsessive beer nerd that I am I wouldn't normally go to the same lecture twice. But when I was invited to hear Ron Pattinson talk about stock ales in London I couldn't say no, despite having already heard him give that talk in Amsterdam. It just combined too many of my interests: history, Brettanomyces, and free beer.

I had high hopes about the last one. This event was being run by Goose Island (ABInBev), and their marketing budget easily covers providing enough free beer to make me regret it in the morning. In fact the budget clearly stretches considerable further than that, as they'd flown over a brewer from Chicago again, and Ron got to go over there himself, as well as visit London.

There's definitely something to be said for big breweries with big budgets. It's amazing to see the amount of effort that went into making this beer, and no way are they going to get their costs back from the amount of beer they have to sell.

I'm not going to go into more detail about the beer, as I did that back in July, and anyway, Bryan and Martyn have already written up the night. I will say I had a cracking time though. Long may breweries with big budgets put great efforts into re-creating historic beers, and giving me free samples!

Saturday 24 September 2016

The past and future of hops

The latest IBD meeting I attended was about the perennial favourite hops. First we had Dr Peter Darby of Wye Hops showing us round the hop collection at Queen Court Farm. 

There are 250 varieties growing here, historic varieties and interesting breeding lines.

It's a whopper
All dwarf varieties are descended from this male
 We got to hear about hop history too, including I'm pleased to say the importance of Farnham.

Mathon may be in the midlands but this plant originated in Farnham
Then it was back to Shepherd Neame brewery to hear some more fascinating facts.

Several topics were covered in the talk.

When Wye College was closed down by the institution I studied microbiology at great efforts were made to save the hop collection.

The main site is at China Farm, and Queen Court acts as a back up.

The changing taste in hops has led to a re-evaluation of the varieties in the national hop collection.

Already Keyworths have been returned to production, and we can now add OZ97a, now known as Ernest. It's named after Ernest Salmon, the great hop breeder, as it's one of his varieties.

As every hop seedling is a new variety there has been a proliferation of new varieties in recent years, not just from hop breeders but also hop growers and hop merchants.

At Wye Hops they changed direction to start breeding for flavour in 2011, taking Cascade as their starting point. In England it crops very late so it was bred with early males to try and bring this forward. Breeding for specific oil and inbreeding to increase desired characteristics was then carried out. Cascade itself the result of a lot of Fuggle inbreeding (and Citra is a result of Hallertauer mittelfrüh inbreeding). Hop merchants Charles Faram have open pollinated Cascade  to get Jester and Olicana.

Efforts to breed a wilt-resistant Fuggle have also continued and after at least 60 years finally seems to be bearing fruit. Or should that be cones?

The English hop breeding programme has beer based on Goldings, as though they're susceptible to wilt they carry genes (presumably recessive) for wilt resistance. Fuggles have no resistance at all but it has finally reached the stage that three Fuggle seedlings have been bred with wilt resistance. 

They are now undergoing farm trials and look very promising.

Resistance to aphids has been a continuing focus, as apart from Boadicea, (which only makes up 3% of the crop) all English hops need spraying for aphids. A problem is that Boadicea and its progeny have a very distinctive smell, which many dislike. In 2014 a selection was finally made of a seedling without this characteristic. 

Advances in genetics have allowed precision breeding using marker assisted selection to start taking place.

Early genetic investigations into hops were too crude to be of use to hop breeders.

But over the years techniques have become more sensitive to the point that known genetic markers can be tied to traits seen in the phenotype.

SNP (Single Nucleotide Polymorphisms) can now be used to screen seedlings for traits as early as six weeks after sowing, greatly increasing the speed and efficiency of hop breeding.

It is not however without its problems, and is still to expensive to use for all seedlings.

A series of crosses have been made from four hops varieties to find markers for four types of characteristics: Fuggle (traditional), Cascade (new), Pilgrim (disease resistance) and Boadicea (aphid resistance)

This is being carried with a number of different institutions, and it is possible that it is from one of these places that Peter Darby's successor will come.

New challenges are still affecting the hop industry and climate change is one of them. People are now looking for drought resistance and it is now not just Bramling cross that is failing to thrive due to Winters being too mild. After this excellent talk no-one could argue with the final point that more hop research is essential!

Friday 16 September 2016

Some clarity on finings

Once again it's clear there is still a lot of confusion about finings. Finings are used to help make beer clear by causing haze forming particles to clump together and thus drop out of suspension faster.

The confusion comes because there are different types of particles that cause different types of hazes and different types of finings are used to remove them.

  • Copper finings originate from seaweed (irish moss), have a negative charge and are added in the copper (kettle) to help remove protein.
  • Auxiliary finings can also originate from seaweed or can be silicate based. They have a negative charge and are added to the fermenter, conditioning tank or cask to help remove protein.
  • Isinglass finings originate from the swim bladders of some tropical fish. They have a positive charge and are added in the conditioning tank or cask to help remove yeast.

A large reason for the action of the finings is due to the charge they have. Opposite charges attract so negatively charge finings attract proteins (which are positively charged), and positively charged finings attract yeast (which is negatively charged). This is why finings cannot be used interchangeably and finings made from seaweed will not help remove yeast. Neither will PVPP so don't start on that. Or silica gels either. If you're after more information I recently posted at great length about hazes caused by non-microbiological particles, and part two on microbiological hazes is in the latest issue of the SIBA journal and will be posted here in due course. 

Thursday 15 September 2016

Dealing with beer haze part one

Beer hazes can be divided into microbial (i.e. caused by bacteria or yeast) and non-microbial. There are also various types of non-microbial hazes, but the most common is that caused by protein-polyphenol complexes and I will focus on that in this article.

Protein-polyphenol complexes are a major component of trub, hot break, cold break, chill haze and some permanent hazes. They are formed when haze forming proteins bind with haze forming polyphenols (tanninogens). When these complexes form particles large enough to precipitate they cause a haze. At first these particles are less soluble at lower temperatures so reversible chill hazes can appear when beer is cooled.

Predominantly they originate from the malt but a number of factors at various stages of the brewing process can contribute to their existence. This goes to the very start of the brewing process, as the correct mineral composition of brewing liquor is important to prevent their formation. Calcium levels in brewing liquor should be greater than100mg/l and the residual alkalinity as carbonate should be less than 50mg/l. Calcium has the effect of lowering the pH of the mash, and carbonate will keep the pH high. You should aim for a mash pH of around 5.2 to 5.4. If the pH is too high more polyphenols will be extracted from the malt and the beer is more likely to be hazy. The most common way of removing carbonate is to add food grade acid to the Hot Liquor Tank, and calcium salts can be added by mixing them in with the grist. The choice of acids and salts used will affect the chloride/sulphate ratio of the beer which will have some effect on the flavour.

The protein component of hazes will come from the malt and if the total nitrogen content is over 1.65% haze is more likely to form. Protein content can be lowered by using a proportion of low protein adjuncts, such as sugar or rice, to make up some of the extract. It is also possible to get malt from barley varieties that have been bred to remove the haze forming polyphenol proanthocyanidin. The use of “ProAnt” free malt will reduce the formation of haze in beer.

Over sparging of the mash will cause more polyphenols to be extracted into the wort. The more the mash is sparged the more it will lose its buffering capacity and the pH will start to rise. To prevent high levels of tannins being extracted stop sparging when the gravity of the last runnings has dropped to 1.005.

During the boil the hot break will form as proteins coagulate, which can be removed as trub with the hops. Copper finings, a polysaccharide derived from seaweed, should be added towards the end of the boil to aid cold break formation and the subsequent removal of more protein-polyphenol complexes. The addition rate for copper finings should be optimised as over or under addition will give poor fining action. Ideally the addition rate is optimised for each batch of malt.

Polyphenols from hops will be extracted during the boil and can contribute to haze, particularly in highly hopped beers.

Protease enzymes can be added to the fermenter to break down haze forming proteins. This also has the benefit of making the beer gluten free! Auxiliary finings, polysaccharide or silicate based, can also be added to the fermenter or conditioning tank and will also help with protein removal. They can even be added to the cask, but should not be added at the same time as isinglass finings or they will bind to each other!

Other processing aids available to brewers can also help reduce haze. Silica hydrogel or xerogel will also help remove haze forming proteins, and PVPP can be used to remove haze forming polyphenols. These products are available in a mix containing both of them, which is usually added prior to filtration, though they can be used without filtration and left to settle in a tank. Rather counter intuitively tannins can also be added to beer to help clarify it. Adding an excess of polyphenols in the form of tannic acid means more protein-polyphenol complexes are formed and can be removed in the brewery.

The fact that more haze forming particles come out of suspension at lower temperatures can be used to our advantage. Cold conditioning prior to filtration, at a temperature of 0ºC or lower, will maximise the amount of haze particles removed and make a clearer and more stable beer.

This post comes from a talk I gave at the SIBA conference that I then wrote up for their magazine.

Sunday 4 September 2016

Brettanomyces flavour

The trouble with serious writing is it's bloody hard work. I've been doing some serious writing on Brettanomyces of late and it's been a painfully slow process grinding out the words. Still, I have found some fascinating facts. 

Whilst looking into the Brettanomyces flavour wheel I came across some slides of a study into whether the flavours produced by 83 strains of Brett. were thought to have a positive or negative effect on wine. No admittedly Brett. has a worse effect on the flavour of wine than it does beer* but the study highlights a problem of brewing with Brettanomyces: a lot of the flavours it can produce don't taste very good.

* Ha!