What on earth is a wort?

When I started brewing it took me a while to get the whole wort concept, what it is and how to do it right. So what is wort?

The wort is probably the most crucial part of the brewing process, and if done right will make a great beer. The wort is the mix of malted water (from mashing using all-grain or BIAB, or from malt extract) and hops being boiled (must reach a boiling stage) to do several things:

1. Sterilization – when making beer we add many ingredients that are completely natural – malt, hops, maybe some fruit or spices; every one of those ingredients spent time in nature and might bring in contamination to spoil our fermenting beer; the boil kills all of those.

2. Protein Break – the extracted malt has many proteins that come in a 3 dimensional structure made from amino acids. We need to break those big protein molecules into the smaller amino acids with high heat, hence the boil; in turn, those amino acids go through the next stage:

3. Combining Proteins and Tannins (Hot Break) – once the proteins are broken down to smaller molecules they can combine with tannins in the malt (tannins are acid molecules) in order to create a clear (unlike cloudy, or unfiltered) beer. The proteins and tannins continue to collide and combine until a critical mass that is called a hot break – when the wort clears up and particles are floating in it (like egg soup). The hot break must be reached in the wort stage to get a clear beer.

4. Extracting Alpha Acids – we add hops to the beer in the wort stage in order to extract alpha (and beta) acids from the hops to the beer. Alpha acids are the bittering acids that give beer its unique taste and bitterness. The boiling increases the efficiency of the acids extraction and the longer they are boiled, the more acids are extracted. The other side of boiling hops is that the volatility and evaporation causes a loss of aromas.

5. pH Reduction – boiling the water and creating evaporation also encourages the evaporation of minerals from the water resulting in a decrease of the pH, leading to a “softer” beer.

6. Colouring – the sugars in the malt tend to be darkened at a high temperature (just like making caramel), so longer boils darken the wort. Also, during the boil there is evaporation of water that leads to a concentrated wort – and so a darker wort.

7. Potential to Increase Gravity – gravity is the sugar density in the finished wort by which we measure ABV. If we add sugars at the beginning of the wort we can increase the sugars in the final wort, creating a higher gravity than the malt water offered us.

Now to the bread and butter – the boil process

The boil process is what actually happens to the wort, and here are a few actual steps for doing it:

• Recommended boil time for the wort is 60 minutes. You can either start measuring from the point of boiling or from the start of the cooking time. A boil can be longer or shorter (obviously).
• For extract malts (liquid or spraymalt) the boil time can be as short as 15 minutes. Extract are non hopped concentrated worts, so they don’t need long to reach a hot break.
• The wort must reach a boiling temperature – that is over 100°c (212°f), this has to happen to create a good beer.
• Recipes (the laconic ones….) present the time in which the hops are added to the wort (60 mins, 35 mins, 0 mins etc). Sometimes the time is counted forward (from 0 on) and sometimes backwards (a countdown), so look at the recipe closely.
• I suggest combining all the ingredients in the pre-boil and put it on high heat straight away to start a boil.
• It is important not to introduce air into the hot wort to avoid recreating cloudiness in the beer. After the wort has cooled down to 27°c or less, air can be introduced (pouring it or giving a good stir etc)
• After the hot break, at the end of the boil time, we want to create the opposite effect to keep the cold wort (and then beer) clear. The opposite effect is called cold break and the best way to achieve it is an ice bath. Fill your sink with cold water and ice; put the kettle with the wort inside it and let it reach a temperature lower than 27°c, after that you can strain it into the fermenter.

 Troubleshoot

The biggest problem that boiling a wort presents is spillover. When the wort is boiling, and the proteins are wildly colliding and combining, they create a hot “crest” at the top that leads to overspills. The best way to avoid is to constantly stir the wort, especially after adding hops (they make the wort go wild!).

The thing with spillovers as that they will happen, especially if you are not well organized and leave the stove top for a second. Stay organized in setting everything for the boil and keep stirring past the hot break (when spillovers are less likely).

That is all there is, on one leg, to know about what is a wort – what it does, why and how. This is by all means not all there is to know about the wort, and the complexities here are endless, but to make a beer and understand the basic and most important part of it, this is all you need.

For more information you can get John Palmer’s book, or look at the relevant online chapter here.

Not sure what I meant, or think you have something to add? Leave a comment and lets talk about it.