Getting to know your ingredients – Hops

There is a story that India Pale Ales were the creation of George Hodgson and his Bow Brewery of London. In the early 1750's when there was a call for home comforts in British colonies in India, Mr Hodgson found himself in the right place at the right time.

His beers, often Porters or October beers were held in high regard within the colonies. The time at sea in often warm climates significantly aged his product. The pale October beers faired particularly well as they were very high in alcohol content and balanced with a healthy addition of hops. They were perfectly matured and well received upon arrival in the East.

Although probable that the Bows Brewery beers were quite excellent, their success was likely, at least in part due to their location, near the Docks of the East India Company. Throw in a generous line of credit permitted to his customers and George Hodgson had the ticket to monopolise the market of ex-pat's and the serving military in India.

The brewery changed hands within the family a few times and in the 1820's the brewery decided to ship the beers to India themselves to maximise profit. On top of this, they turned their back on the long standing arrangement with the East India Company, and along with hefty price increases, credit was no longer taken and sales became a cash only arrangement. About 25 years later, with out the might of their former business partner, the Bow Brewery shut up shop with the then owner, Fredrick Hodgson, reportedly fleeing to Paris with the wife of an Indian army officer.

Of course like most 'stories' there are some irregularities. Firstly pale, strong, hoppy beers like the aforementioned October beer were shipped to India long before George Hodgson was on the scene. Also the term India Pale Ale was not recorded prior to the 1830's, with one of the first advertising their product as such being Bass in 1841. So George Hodgson may have been an entrepreneurial legend creating a successful brewery which traded for almost a hundred years but the “Godfather of IPA's”? Probably not. What is credible however, is that accompanying a high ABV, hops and their preservative properties have greatly influenced the type of beers available in the wider world over the last three centuries.

...which brings me conveniently to the topic for this blog; Hops.

When referring to hops, brewers will be referring to the female flowers of the plant Humulus Lupulus. This incredibly complex and diverse flower imparts three main characteristics on our beers. Bitterness, Flavour and Aroma.

In truth, the subject of hops is extremely extensive and many a book is devoted solely to the topic. As these short blogs are intended only as a summary into the world of brewing, I will bullet point what I believe are the main areas of relevance for the home brewer; 

Bitterness – Lupulin glands within hops contain a key contributor to bitterness, Alpha Acids (AA) When purchasing hops, the AA% should be detailed, the higher the content, the more bitterness it should impart on our beer. Most hops considered 'bittering hops' will have a high Alpha Acid content. When boiled, the Alpha Acids become Isomerised and it is these Isa-Alpha Acids which increase IBU's (International Bitterness Units). The longer the boil, the more bitterness we can extract, up to about 90 minutes, at which time, we'll probably have all we can from our hops, without undesirable characteristics. Hops boiled for the amount of time necessary to extract high levels of bitterness generally offer very little in terms of flavour or aroma.

Flavour – Essential oils within hops create many flavour compounds. From spicy, earthy flavours of classic English hops like Kent Golding and Fuggles, to the popular citrus and fruity flavours of many American hops like Cascade and Amarillo. Flavour hops additions are regularly added half way through and towards the end of a boil . The closer towards the end, the more flavour, but less bitterness they impart.

Aroma – To get the most aroma from hops, you would add them at the end of the boil, or often post boil. Many techniques have been developed in recent years to increase aroma, including 'whirlpool hops' which are added when cooling the wort to pitchable temperatures, whilst stirring or pumping wort in a circular motion to centralise the debris before extracting to the fermenter, leaving the trub behind. The more popular way of getting a great aroma from hops is 'dry hopping'. This involves transferring the beer to a secondary vessel after the main fermentation is complete and then adding a dose of hops.

Hops are not yet fully understood, and could command a full PhD to get anywhere close to scratching the surface, but in my opinion, you can't often go wrong on a homebrewing level by following this principle;

Higher alpha acid levels and longer boil times extract more bitterness. Less time boiling allows more flavour compounds to come to the front and adding hops without boiling them at all lets the aroma shine through. Also, don't be afraid to give your hops a good sniff. This will give you a good idea what characteristics they will give you.

Luckily, today there are several varieties of software such as 'Beer Smith' and the free 'Beer Engine' which help us predict bitterness levels. These along with experience and recipe books help us predict what hop schedules are suitable for our own recipes.

A comprehensive account detailing hop varieties, their properties and characteristics can be found here. I would also highly recommend "For the love of hops" by Stan Hieronymus as a great read on the subject.

I will talk more about the practical use of hops later in my series of brewing blogs. I hope you enjoyed reading. Please stay tuned for more!