Using hop analyses to optimise the brewing process

May 21, 2020
They say there’s no such thing as a bad beer, but some do taste better than others. We take pride in our hops, and the beers our customers create with them. That’s why quality management is so important to us. We have a range of quality management procedures in place to ensure our farms and facilities are ISO 9001:2015 compliant and HACCP certified. This includes analysing around 3,000 hop samples over the course of harvest, which contribute to more than 25,000 measurements that help us meet customer expectations of consistent hop flavour outcomes year-on-year.

Understanding pre and post-harvest hop analysis is key to producing beer of consistent quality. Hops are a natural ingredient produced by a highly specialised horticultural system in temperate regions around the world, which means they are subject to seasonal variation. Hop analyses give hop growers and brewers alike the opportunity to optimise their processes to achieve consistency and efficiency. This is a very technical topic, so if you don’t have the time or capacity to digest it right now, reach out to your local Sales Rep and they’ll talk you through the high points.

For those of you still with us, the hop sampling and measurement process spans a period of six months. During this time, we go through three phases on quality testing – pre-harvest in-field samples, harvest bale samples and post-harvest packaged product samples:

Pre-harvest sampling tracks the development of hop cones and the accumulation of alpha acids and essential oils across our farms. We systematically sample every paddock across our farms at least three times pre-harvest, with the final sample taking place within 36 hours of the paddock being harvested. The information we receive from these samples confirms whether our planning around harvest logistics is correct, and informs the picking sequence for varieties that cover significant acreage. This picking sequence ensures we capture the best possible representation of each variety year-on-year.

We input proprietary predictive models into a Near-infrared (NIR) analytical system to assess the samples’ alpha acids and oil content. Gland fill, dry matter and cone weight are also measured at this stage. All of these measurements follow a fairly consistent pattern of development in the lead up to harvest, which occurs when the paddock reaches our ideal values. The below graph and associated heatmap provide a visual representation of the day in year that these values are typically reached. However, events such as hot and windy days, heavy rain, flooding or frost can accelerate development.

During harvest we take several composite samples from each lot of hops once they have been baled. Alpha acids and moisture content are the main focus at this point with all measurements produced through NIR. This is crucial to the blending process that enables us to achieve consistent quality outcomes for each variety year-on-year.

Post-harvest we conduct further testing on each lot of final packaged product, including pellets and flowers. The information we receive from these tests is what brewers see on our certificates of analysis (CoAs).

Brewers can use CoAs to anticipate process changes required to achieve consistent brewing results, and to verify compliance with hop specifications. Our hops are supplied in sealed, oxygen barrier laminated foils that have been back-flushed with carbon dioxide and packed in cardboard cartons. Each carton is labelled with variety, producer, crop year, production date, lot identification number, product type, net weight and bittering potential (alpha acid contents and analysis method). There is no standardisation of hop CoA information in the brewing industry. In their most basic form a CoA will cover the same information as the carton labels, but we also choose to include essential oil content, moisture content and agricultural chemical residue reporting.

Each hop analysis has a different siginificance in brewing:

Since hops that are used in brewing are a food ingredient we are required to ensure all typical food safety requirements are met, and can also provide allergen and residue statements if required.

It is also important to remember that hop CoAs and label information describe the hops at the time of packaging. Chemical changes that affect performance in beer may occur if the hops are transported, stored and/or handled improperly at any stage of the supply chain. We work closely and collaboratively with our contractors to ensure this risk is managed effectively, so that our customers can continue making great tasting beer.

 

< Back to all articles

Top