Hop resin is a sticky compound formed in the lupulin glands of the female hop flower. The resins of the hop flower are composed of alpha and beta acids and are chiefly responsible for the bitterness and hop aroma found in beer. Additionally, alpha acids found in the hop resins function as a mild antibiotic and work as a preservative in beer.
Category: Brewing Terms (Page 3 of 10)
A dictionary of home brewing terms.
Saccharification in very basic terms is the conversion of starches to sugars. When it comes to all grain brewing, saccharification is a critical conversion process that occurs during mashing. As the mash tun’s temperature is increased to a range of 120° F to 158° F, the diastatic enzymes of the malted grains begin to activate and break the starches of the grains and adjuncts into sugars. The alpha amylase enzymes break apart complex starches into sugars that the beta amylase enzymes break apart even further into easy-to-ferment maltose sugar.
Precision is critical when it comes to the temperature of a mash and 10 degrees makes a massive difference. Beta amylase is more temperature dependent than alpha amylase, and when the temperature in the mash begins to rise above 158° F, the beta amylase is no longer capable of breaking apart the more complex sugar chains into maltose. So if your target mash temp is 152° F and you instead conduct your mash at 162° F, you will be left with a massive amount of unfermentable sugars in your finished beer, and it will have a fuller body and overly sweet finish.
Beta amylase thrives in a temperature range of 140° F to 150° F, so if your target mash temp was 152° F and you conducted your mash at 142° F, you would end up with a beer with a very thin body and dry finish due to a deficiency of unfermentable sugars. This is the reason why the typical mash saccharification rest temperature is in a range of 152° F to 154° F; it provides a good temperature compromise for both alpha amylase and beta amylase to carry out their required starch and sugar conversion processes.
Milling is the crushing of grains and malt in preparation for the mash. The grains are milled so that the husk is cracked and the internal starches of the malt and grains will be exposed to the enzyme reaction taking place in the mash.
Mouthfeel, or the mouth feel of a beer, is the mouth’s perception of the body of a beer and is typically described as light, medium, or full. A beer’s body is formed from the residual proteins, minerals, salts’ and unfermented sugars that remain in the finished beer. The body of a beer is perceived as viscosity or thickness by the mouth. Each style of beer has a coinciding expectation for mouthfeel, and beers are rated on that expectation. For instance, a lager or pilsner should have a light body, and an imperial stout should have a full body if brewed correctly.
The lag phase is the period of time in which yeast adapts to the new fermentation environment and undergoes significant reproduction. Depending on the state of the yeast (reactivated, chilled, or dried), health of the yeast cells, variety of yeast, amount of dissolved oxygen available in the wort, temperature of the wort, and amount of available fermentable sugars, the lag phase may last anywhere from 2 to 24 hours. The lag phase begins as soon as the yeast is introduced into the wort and very little CO2 or alcohol is produced while it is active.
The shorter the lag time, the better, so that the desired yeast has a chance to take control of the wort before unwanted bacteria or wild yeast strains do.There are several ways to decrease your lag time, including:
- Creating a yeast starter
- Rehydrating dried yeast
- Keeping your yeast and wort at the correct temperature when pitching the yeast and continuing to monitor temperature until the lag phase has ended.
- Well-aerating your wort so that the yeast will have enough oxygen available.
- Pitching enough yeast for the gravity of your wort.
The term noble hops refers to either German Tettnang, German Hallertauer, German Spalt or Czech Saaz hops. These noble hop varieties are all classified as aroma hops and have a relatively balanced alpha and beta acid ratio, which allows them to impart a subtle bitterness and full aroma. Each of these hops has a long tradition in brewing and is named after the region that it was originally cultivated in.
German Tettnang Hop, Alpha Acid 3.5-5.5%, Beta Acid 5-6%
German Hallertau Hop, Alpha Acid 3-5%, Beta Acid 4-5.5%
German Spalt Hop, Alpha Acid 4-5.5%, Beta Acid 4-5
Czech Saaz Hop, Alpha Acid 3-4.5%, Beta Acid 3-4%
Original gravity or OG is the specific gravity reading of a beer’s wort prior to having the yeast pitched for fermentation. The original gravity reading is important because it gives the brewer an idea of how much sugar is available for fermentation and what the approximate alcohol by volume will be once fermentation completes. The original gravity reading also permits a brewer to calculate his or her brew house efficiency to determine what percentage of starches and sugars were extracted from the grain bill used to make the beer. Typically either a hydrometer or refractometer are used to take the original gravity reading.
Below is the photo of a hydrometer which is used to take original gravity readings.
Oxidation is the degradation or modification of beer when it comes in contact with oxygen or an oxidizing agent. Oxidization in beer is inevitable and occurs in beer at all times regardless of how it is stored. That being said, there are ways to diminish the rate of beer oxidation.
A good rule of thumb is to prevent oxygen from coming in contact with your beer whenever possible. The only time that oxygen should intentionally be introduced to a beer is when aerating or oxygenating wort prior to pitching yeast, and, in rare cases, to facilitate a souring process. Great caution should be taken when transferring, racking, kegging, and bottling beer to avoid splashing it or exposing it to more oxygen then is necessary.
When possible, fermentation vessels, kegs and bottles should be purged with CO2 prior to and after having beer transferred into them. Heat is another factor that impacts oxidation, and, whenever possible, beer should be stored cold to reduce oxidation rates and to preserve its freshness. Another way to help slow the impact of oxidation is to keep bottles and fermenters shielded from sunlight.
Beer that has been oxidized typically has a stale or paper-like taste. In darker beers, you may also smell or taste sherry notes.
Beer phenols are chemical compounds, similar in structure to alcohols, that are generated by yeast during fermentation. In certain styles of beer, such as Bavarian hefeweizens and wit beers, phenol flavors such as bubblegum, banana and clove are considered desirable; but in other styles they are considered to be an off flavor or flaw. Causes of unwanted phenols include wild yeast or bacteria, chlorine, and excess sanitizer.
pH, short for potential hydrogen, measures the acidity or basicity of a brewing fluid such as the starting water (liquor), mash, wort, or beer. A fluid with a pH less than 7 is acidic, and a fluid with a pH greater than 7 is basic or alkaline. If a fluid has a pH of 7, such as pure water, then it is considered neutral.
pH is a very important factor in all grain brewing, and different geographical areas and water sources can have dramatically different pH levels and mineral contents that impact the pH of a mash. Additionally, the style of beer that you brew will have a significant impact on your mash pH level. Typically the darker the color of the malts that comprise your grain bill, the more acidic your mash will be. This is important because the enzymatic conversion of starches to sugars only effectively occurs in a mash that has a pH between 5.0 and 6.0; ideally your mash would be between 5.2 and 5.5 pH, which is considered optimal.
A great starting place for dialing in your mash pH is to get a copy of your municipal water report to learn about the pH and mineral composition of your brewing water. Software such as BeerSmith has great tools built in that will help you determine when brewing salt and mineral additions are required to help you bring your pH in line when comparing your local water to that of a specific style of beer. Lastly, purchasing some inexpensive pH testing strips is an effective way to ensure that your mash pH is at an appropriate level.
A wide selection of home brewing pH testing equipment can be found here:
Home Brewing pH testing equipment
Photo of ColorpHast pH testing strips used during the mashing phase of a home brewed beer.
Brewing pH Strips
Mashing is the process of mixing and infusing crushed malts, unmalted grains, and adjuncts with hot water from the hot liquor tank. As the grains and adjuncts mix with the hot water at specific temperatures, enzymes from the malt activate and convert the starches into sugars. At the same time that the starches are being converted to sugars, color is also being extracted from the grains, which is the primary determining factor of the beer’s final color. The mashing process takes place in a brewing vessel called a mash tun.
Below is a photo of crushed grain being stirred in the mash tun during the mashing process.
Grains being mashed during the mashing process.
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