On Using Dry Yeast, Hops and Dogs, and Mash and Brewhouse Efficiency

Homebrew expert Brad Smith, author of the Beersmith homebrewing software and the voice behind the Beersmith podcast, tackles questions about hydrating dry yeast, hops poisoning in dogs, and mash and brewhouse efficiency.

I have some packets of dry yeast. Is it better to sprinkle them on top of the wort or hydrate them with water first?

It is always better to hydrate your dry yeast properly before pitching it into your wort. Dry yeast cells are in a susceptible state in that they cannot properly regulate compounds passing through their cell walls until they have been hydrated. For highergravity worts, in particular, hydrating the yeast before pitching is important.

To hydrate your yeast, I recommend mixing the packet contents with about 25 ml of warm (104°F/40°C) water per gram of yeast. I also like to mix in about 1.25 grams of Go-ferm yeast nutrient per gram of dry yeast. The Go-ferm provides nutrients that aid in hydrating the yeast for an active fermentation.

You don’t want to shock the yeast by changing the temperature too rapidly. Once you have the warm mixture of yeast, Goferm, and water, you need to slowly bring the temperature of it down to that of your wort. To do this, add small amounts of wort

to your hydrated yeast and wait a few minutes between additions. Your goal in this process is to move the yeast temperature less than 10°F (5°C) at a time, and you can pitch your yeast when the mixture is within about 10°F (5°C) of the wort temperature.

If you follow the process outlined above, you will not only provide the yeast cells with proper nutrition for a healthy fermentation but also minimize the chance of shocking the dry yeast cells.

I heard somewhere that hops are poisonous for dogs. Is this true?

Yes, unfortunately hops can be quite dangerous if ingested by dogs and, more rarely, cats. Compounds in the hops can cause a malignant hyperthermia, which results in a rapid rise of body temperature. A dog’s body temperature, which is normally below 102°F (40°C), can rapidly rise to 108°F (42°C) or higher, potentially resulting in permanent damage to the organs and brain or even death.

The exact quantity of hops fatal to dogs is not known, and some breeds, such as

greyhounds, retrievers, Saint Bernards, pointers, Dobermans, border collies, and English springer spaniels, are more susceptible to hops poisoning. For practical purposes, you should consider any quantity of hops to be poisonous to your dog. If your dog ingests hops, he can develop the following symptoms (in addition to a rapid rise in body temperature): redness around the mouth, excessive panting, excitement, abdominal pain, seizures, and rapid heart rate. These symptoms may occur anywhere between 30 minutes and 12 hours after the dog consumes the hops. Treatment includes cooling the dog, induced vomiting, charcoal, and efforts to clean its digestive track. If you think your dog has ingested hops, try to cool it as much as possible and immediately take it to a veterinarian or animal hospital for treatment. Only a doctor can properly treat a pet for hops poisoning. Obviously, prevention is the best course of action, so if you own a dog or cat or have other pets in the neighborhood, you should take care to bag and properly dispose of your spent or old hops. You should never mix spent hops with your grains and add them to a compost pile where animals may gain access to them.

What’s the difference between mash and brewhouse efficiency in allgrain brewing, and how can I improve my efficiency?

I’ll start with an explanation of mash efficiency. First, you need to understand that each individual grain you use has its own “yield.” The yield is a percentage that represents the percent of the weight of the grain that can be converted into sugar under ideal laboratory conditions. An average pale malt might have a yield of about 80 percent, meaning that 80 percent of the sugars could be converted and extracted in an “ideal” laboratory setting.

A real-world brewing system outside of a laboratory does not achieve this perfect number. In fact, a typical brewing system is only going to get perhaps 80–90 percent of the potential sugars extracted during the mash, meaning that 80–90 percent of the yield will be achieved in the runnings coming directly from your mash tun. The

portion of the “ideal” number your system extracts during the mash phase is called the mash efficiency.

Of course, the mash itself is only one step in the brewing process. After mashing, we may add top-up water, boil, chill, and transfer the wort, all of which results in some further losses due to trub loss, chilling, and transfer losses into the fermentor. These additional losses result in a lower original gravity of the wort into the fermentor than we achieved coming out of the mash tun.

The overall efficiency of the system from mashing grains to gravity points in the fermentor is called the brewhouse efficiency. It represents how well the complete brewing system converts potential sugar in the raw grains into original gravity points (sugars) in the fermentor. This number is always lower than the mash efficiency due to the additional losses in these later steps and is typically in the 65–75 percent range for many homebrew systems.

Many new all-grain brewers struggle with low efficiency numbers, resulting in lowerthan-expected original gravity for their beer. Some of these inefficiencies can be corrected through experience. As you become more familiar with all-grain brewing, your efficiency will often improve.

Another solution is to simply lower the brewhouse or mash efficiency estimate you are using to develop your recipes. This will effectively cause you to use a bit more grain in your recipe but should allow you to hit your original gravity with only a dollar or two of extra grain added per batch.

If you truly are experiencing low efficiency in your batches, the next item I recommend looking at is your grain crush. The crush of the grain can have a huge impact on the efficiency you will see from your brewing system. I’ve had cases where a grind that is too coarse, often from grains crushed at a store, can result in low gravity numbers.

The ideal grain crush is actually pretty fine. The inside of the grain should be crushed to fine granules, but you should still have large pieces of the grain husk left intact to act as a filter bed. It is a delicate balance, however, for if you crush the grains too finely you can end up with a “stuck sparge” that will gum up your mashtun filter and prevent proper lautering.

If you have properly crushed grains, then the next item to look at is your sparging/ lauter process. Make sure you are sparging with hot water at the proper temperature. The sparge water should be at least as hot as your final mash step, though it is not uncommon to sparge with slightly hotter water to improve the viscosity of wort during sparging and extract more sugar.

Also, in general, a slow sparge will extract more sugars than a very fast one, so try taking your time during the sparge phase to slowly draw wort from the bottom of your mash tun. In some cases the design of the mash tun can play an important role as well—ideally you want a mash filter that covers the entire bottom of the tun so you can draw wort off evenly and avoid channeling in the grain bed.

Finally, look at losses in every phase of your brewing process. Wort lost below the mash-tun spigot, in transfers, in your chiller, in the trub left in the boiler, and even in hoses or pumps represents lost sugars and will lower your overall efficiency. Reduce losses whenever possible for a more efficient brewing system.

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