Archives for April 2023

Don’t Overpitch a Session Beer

[This is the second article in a series on brewing session beers. In the first, I discusssed sparging the grain bed for a low-gravity beer.]

In the past, a common problem among homebrewers was pitching an inadequte amount of yeast. The original containers of liquid yeast did not contain enough yeast cells to yield an ordered fermentation of 5.0 gallons (19 L) of average strength or higher wort. They “would work,” but start times were longer than they should have been and sometimes the beer did not attenuate fully. However, some brewers did not want to go through the hassle of making a yeast starter. 

These days, homebrewers have access to liquid yeast packs that have 100 billion cells or 200 billion cells. And of course, we’ve always had access to dried yeast packets that have a large cell count. An 11.5-gram packet of dried yeast, for example, contains over 200 billion cells. And all that is great —  except when you are brewing a session beer. For a low-gravity beer, the amount of cells in a commercial yeast packet might actually be too high.

Generally, the problems associated with overpitching are less troublesome than the problems associated with underpitching. However, in a session beer, overpitching can detract from the beer’s character. Overpitched beers may attenuate to a greater degree than you want. With a session beer, you already expect a low finishing gravity because of the low starting gravity. So “extra” attenuation is unwelcome. You can moderate this somewhat by adding more crystal or caramel type malts to your recipe or mashing for a shorter time at a higher temperature. However, higher pitching rates also increase your overall attentuation. 

In addition, the yeast character from ale strains is mostly developed in the early growth phase of the beer fermentation. Fewer esters are produced once the yeast has reached their maximum density and are fermenting compared to when the population is still growing. So, overpitching can minimize the yeast character of a session beer. And given that many session beers are low-gravity, English-style ales, this character will be missed. Even in a non-English-style beer, some yeast character in a low-gravity beer gives it more overall aroma and flavor — something that can be lacking if the beer is not brewed well.  

For a low-gravity ale, I recommend pitching even less than the typical ale calls for. The general rule of thumb for ales is to pitch a million cells per mL per °Plato. So, for example, 5.0 gallons (19 L) of 12 °Plato (SG 1.048) beer — one that should produce a beer around 5.0% ABV — would need 227 million yeast cells. However, 5.0 gallons of a 9 °Plato (SG 1.036) beer — one that should produce a 3.5% beer — only needs 170 million cells. Pitching 200 million cells to a beer like this would not be drastically overpitching, and you’d probably get away with it. However, if you wanted to purposely underpitch to develop more yeast character, 130 million cells would be a better target. That’s 75% or the amount the general rule would suggest (and in line with the pitching rate of many commercially produced ales). 

Fortunately, it is easier to deal with having too much yeast than too little. If you have a 200 billion yeast cell container of yeast, and you want your pitching rate to be less than that, just pitch part of the package. If you wanted 130 million cells, for example, you want to pitch (130 million cells/200 million cells =) 0.65 or 65% of the yeast in a 200 billion cell package. Be sure to shake the package so that the yeast is evenly distributed before dividing it. You could perhaps utilize the unused yeast to make bread, or another yeast starter, if you were concerned about wasting it.

Alternatively, you can use a yeast pitching calculator to determine the size yeast starter that would be required. Then, pitch a small amount of yeast to the starter — NOT the whole pack — and let that grow. Recall that 8.0 fluid ounces (240 mL) of yeast slurry is generally adequate for 5.0 gallons (19 L) of 12 °Plato (SG 1.048) beer. So, if you were making a 1.0 qt. (~1 L) yeast starter, about 1/20 of that volume — 0.4 fluid ounces (12 mL) of yeast slurry would be required. I nearly always make a yeast starter because I can assess the health of the yeast based on the vigor with which they ferment the starter wort.

Brewing a high-quality low-gravity session beer requires every bit as much attention as brewing a big beer. The “tricks” are just different. For starters, don’t use too much sparge water on your grain bed nor pitch too much yeast to your wort. More session beer posts are in the works.

Monarch Project Off To Slow Start

I am hoping to raise and release 240 monarch butterflies this year. However, my project is off to a slow start. My garden received a few visits from female monarchs in late March, but none that I have seen since. The weather has been unusually cool and additionally, monarch numbers are down this year. So, either one of those factors, or both, could be to blame. I have plenty of milkweeds in my garden and more blooming flowers than I have ever had. But I need gravid females to visit the garden.

I have two butterfly enclosures (left) that I place milkweed plants in. The caterpillars I capture are placed on those plants. Three of my 20+ monarch butterfly chrysalises (right) currently developing.

I currently have over 20 chrysalises in my enclosures, but few caterpillars to back them up. I need a fresh wave of eggs and subsequently caterpillars. Of course, every year the arrival of monarchs is episodic. And good weather in May — and a bit of good luck — could turn everything around. The spring monarch migration through Texas is still in its early stages. However, this is a disappointing start.

Choosing Tomato Transplants

You can start tomatoes from seeds, but many gardeners buy seedlings (or transplants) in the spring. Choosing the best transplants will result in tomatoes that rebound quickly from being transplanted, grow vigorously, and yield the best crop. Fortunately, choosing the right transplants is straightforward. Except for one thing, all of the criteria for choosing the best transplants are fairly obvious. 

When looking through tomato transplants at a nursery, your first goal should be to identify the healthiest plants. Yellow leaves, which can often be found among the lowest leaves on the plant, indicate a lack of nitrogen. A purple cast, especially around the edges of leaves, is likely to be a phosphorus deficiency. This is less common than a nitrogen deficiency. Tomato seedlings should be a moderate to dark green — but not blue green, as that is evidence of too much nitrogen. And, obviously, they should not be wilted. Wilting could be due to a lack of water — in which case it is easily solved — but it could also be a sign of more serious problems. Young tomatoes — transplanted into well-drained, fertile soil — can quickly overcome early nutrient or water deficiencies, especially if they are minor. However, it’s best to start with the healthiest plant possible. 

Yellow leaves, most often seen near the bottom of transplants, are a sign of a nutritional deficiency. Deformed leaves may be the result of disease. Transplants can quickly overcome mild nutritional deficits.

When looking at transplants, also look for holes in the leaves, which may be indicative of an insect infestation. The leaf damage in and of itself is not particularly worrisome. However, some insects — such as white flies — carry diseases that can manifest themselves when the plant is larger. Also look for leaves that are curled, blotchy, or malformed, as this may be the fist signs of disease. Avoid these plants. 

The final thing to look for in a tomato transplant may seem counter-intuitive — look for the smaller transplants (among plants in same-sized containers). Tomatoes are often sold in tiny 4-well flats, 4″ planters, or in small cups that hold a little more soil. Much of the time, nursery transplants have overgrown their planter by the time they are on display. They can look healthy, but they are rootbound. Nurseries offer these transplants because people want to buy large plants. They think they are getting ahead that way. If there is a table of tomato transplants at a nursery, you almost always see people crowded around the largest plants.

Sometimes, the plants for sale already have flowers. And people obviously like to buy them, apparently because they think they will have tomatoes soon. However, early flowering is not desirable as it is indicative of the plant having switched from rapid growth to an attempt at reproduction. You may get tomatoes fairly quickly, but they will likely be small and the rest of your crop with not be very abundant. 

When you take overgrown transplants out of their container, the roots will be a tangled mess, pressed against the sides of the container. The above ground foliage can look healthy. However, once planted it will take time for a rootbound to acclimate. They will be slow to start vigorous growth. Rootbound tomatoes will rebound with time, but you are better off starting with smaller transplants. These will quickly start growing vigorously and — if you plant at the right time — be the right size when it it is time to flower and set fruit. 

This plant is roughly twice as tall as its container. Its roots have grown to the sides of the planter, but are not excessively tangled or knotted. It should quickly rebound and resume vigorous growth when planted.

A reasonable rule of thumb is that the transplant should be less than three times as tall as the container it is growing in. Optimally, I think that when a plant is twice the height of its container, it is fairly large, but small enough that it will acclimate quickly when planted. Because it is not rootbound, it was likely growing quickly inside its container. And it will continue this vigorous growth‚ after a very brief period of acclimation — when put in the ground.

That’s really all there is to choosing transplants. Pick a healthy, green plant — one that is small enough that it is still growing rapidly in its container — and you are off to a great start.

Don’t Oversparge When Brewing a Session Beer

Session beers are low-alcohol beers that allow the drinker to consume a few without becoming too intoxicated. In order to be of high quality, the brewer must pay just as much attention to brewing a session beer as he would to brewing any normal or high-gravity beer. In the next week, I am going to post a few articles with tips on how to make the best session beers. Today’s entry concerns how much wort to collect from the mash.

A session of beers at the pub can lead to stimulating conversation and a wonderful time.

A fully-sparged grain bed has been rinsed of all the sugars the brewer can obtain without extracting excess tannins and silicates. On my homebrew system, using my methods, I can yield around 0.65 gallons per pound of grain (5.3 L/kg). If I collect a volume short of that, I have left fermentable carbohydrates behind. If I collect more than that, and I risk astringency. This has some implications when brewing a low-gravity session beer. 

Below a certain original gravity (OG), a fully-sparged grain bed will yield a volume of wort less than can be boiled for 60 minutes and still yield 5.0 gallon (19 L). In fact, below a certain OG, a fully-sparged grain bed will yield a volume of wort smaller than your batch size. When this happens, the brewer will need to add water to make up his or her full-pre-boil wort volume. 

Below is a chart that shows beers with target OGs in the session beer range, how much pale malt would be required to hit that target (assuming 75% extract efficiency), and the volume of wort the brewer should collect. Use the chart as a guideline, but also measure the pH and specific gravity of your final runnings if you fly sparge. You can also simply taste the runnins to see if astringency is beginning to show. Once your grain bed is fully sparged, simply add water to hit your desired pre-boil volume. It’s that simple. 

First Monarch Caterpillars In My Garden

I’ve got caterpillars in my garden. The eggs from the first wave of female monarch butterflies started hatching a couple days ago. They took longer to hatch than usual, probably because the weather was a cooler than average in the days after they were laid. Finding monarch eggs on milkweed is fairly hard because they are small and usually on the underside of a leaf. Finding monarch larvae (caterpillars) is much easier — just look for a hole in the leaf. When a caterpillar hatches, the first two things it does are eat the egg casing then chew a small hole in the leaf. It will then expand the hole a bit before crawling off to start feeding in another location. It may do so to prevent other insects from finding it easily and eating it.

A hole on top of a milkweed leaf (left) and the same hole and caterpillar under the leaf (middle). A second example of a monarch caterpillar next to a hole in a leaf.

Monarch larvae develop through five stages, called instars, before forming a chrysalis. The caterpillars in the photo above are first instar caterpillars. The caterpillars below have molted once and are second instar larvae. Each successive instar is larger than the previous one and its coloration pattern is different. First through fourth instar caterpillars are most often found under leaves. They eat nearly constantly, except then they stop to molt.

These second instar larvae are feeding on butterfly milkweed seedlings.

So far, I have set up two butterfly enclosures on my driveway, near my milkweed plants. When I capture a caterpillar, place it on a butterfly milkweed seedling and place the seedling in the enclosure. I have collected over 30 now. Once they have eating most of these seedlings, I will transfer them to larger host plants. (I will put the seedlings back in the sun and they should recover fairly quickly.) My quest to raise and release 240 monarchs is off to a fast start, but there is still a long way to go. I should have chrysalises in a little over a week.