Few beginner questions about temps, SG and yeast

Question

I brewed my second ever batch of beer on the weekend (the first one tasted okay but was flat, I guess I didn't put enough sugar in when bottling). and I have a few questions. I'm using a 5L glass carboy and I brewed using an all-grain recipe using the BIAB technique. I bought a kit for a galaxy smash IPA which included the milled grain, hops, yeast, and a recipe card.

The recipe I am using is for 20L so I divided everything by 4. It's a bit light on in detail so I made some best guesses throughout it that I hope were right!

The recipe says to mash @ 66C for 60 minutes then mash at 76C for 10 minutes.

• how important is it to get exactly those temperatures? I was using a big pot on my gas stove and I had to keep switching the burner on and off. I maintained it within +/- 5 degrees
• after I finished mashing, I sparged (optional from what I could see, but I did it anyway) and then boiled for 60 minutes, and during the boil is when I added the hops (not during mashing) - is that right?
• after cooling the wort to ~25C and immediately before putting it in the carboy, I took a SG reading which was 1.052 on my floating hydrometer / 1.054 on my brixmeter. The recipe says that the OG should be 1.063. Is this difference a problem or okay? Should I still expect to reach the FG listed on the recipe (1.011)?

The recipe card said to use Kviek yeast, but the kit itself came with US-05. The recipe says to ferment for 6 days at 30C (dry hop day 3, cold crash day 6). I did the brew on the 15th and put it into my temperature controlled fridge at 30C. The next day it was fermenting away quite well, but then about 24 hours later the fermentation seems to have stopped (I dry hopped it this morning and the water in the airlock has been pushed back to one side so it must still be generating some CO2, I just can't see any activity).

• will using US-05 instead of Kviek yeast affect the temperature I need to ferment at, or how long I need to ferment for? I did some searching today and it looks like US-05 likes to be fermented at 19-22C, not 30C that the recipe calls for. Have I ruined my beer by fermenting at 30C for a few days? Should I change the temperature and/or how long I leave it to ferment?
• the first brew I did said that I should keep it fermenting until I get the same SG reading two days in a row. Is that the rule I should always use, or should I be sticking to the 6 days this recipe calls for?

The recipe has no information about bottling. Should I just be following standard guides online for how much sugar to add when bottling or is it recipe specific?

Thanks :)

Answer 1

Congrats on a successful second batch! Everything you did looks OK overall. Specifics:

• The 66C temperature is a good goal. If you maintained within a few degrees of that, you will be in good shape. What you want to avoid is going higher than about 73C, because at that point the enzymes will denature very quickly, especially the beta amylase which is very temperature sensitive and is responsible for high attenuation which leads to low finishing gravity (FG). You might see a small impact on FG from temperature fluctuations, but the impact should be pretty minor in your case. Meanwhile, the 76C step is a waste of time for homebrewers, and can safely be skipped, but doesn’t hurt (or help) anything.

• Adding the hops during the boil is usually correct… but for an IPA you will often add most of the hops in the last ~5 minutes of the boil, or at flameout, or as dry hop additions after fermentation has begun. If you boiled most of the hops, you might experience the ceiling limit for IBUs of about 90 IBUs, which is very bitter indeed but which won’t hurt anything as long as you enjoy very bitter beer (like some IPAs). Later additions of the hops will improve flavor and aroma characteristics. Consider doing that next time if you didn’t this time, along with your dry hop addition(s).

• If your OG was a little low, it is not a big deal, but you can expect your FG to also come out a little lower than anticipated. Meanwhile, from first bullet above, the two effects on FG might serve to cancel each other out. You will, however, definitely have a lower ABV than anticipated.

• Kveik yeast is good for high temperature fermentations >22C. Other yeasts such as US-05 are less predictable in their characteristics above that temperature, might turn out OK, but might cause additional fruity esters or solventy fusel alcohols which can lead to headaches and hangovers. I would say: it’s not ruined, but might give you headaches potentially. If you try a non-kveik yeast in the future, keep fermentation temperature closer to 18-19C if you are able. If you need to ferment warmer, then use a kveik yeast.

• Warm fermentations such as at 30C will tend to go VERY quickly and often done in 24-36 hours, which is what you are experiencing. The fermentation is most likely already complete. Why your recipe says to wait 6 days, seems to be mainly for the benefit of the dry hop charge, otherwise there would be little need to wait. One other benefit might be clarity, it gives more time for the yeast to settle out to minimize haze. But your batch is probably safe to bottle or keg in the next couple of days, after the dry hops have had 2-3 days to soak in. To confirm, check the SG today, then rule of thumb is to wait another 3 days, then check again. If SG has changed at all, then it isn’t finished, and you wait another 3 days. If it stays constant for 3 days, then it is safe to package. Two days in a row might be OK for kveik yeast or hot fermentations, but for standard ferments at about 18-19C, the 3-day rule is best. So in your case… you can probably go with the 2 days in a row thing which is applicable more for kveik ferments, since you fermented warm at 30C.

• I’ve bottled >160 batches since 1999. What I’ve found that works best for bottle priming is: 2 tablespoons of table sugar per gallon. Or I guess in metric that might be 1.6 teaspoons per liter. In 4L (which is probably close to what you’ve ended up with), I would use 6.3 teaspoons or 2.1 tablespoons. If you actually do have closer to 4.5L of actual beer volume (without dry hops and yeast/trub), then use 7.1 teaspoons or 2.4 tablespoons. You don’t need to be this exact, but it sure doesn’t hurt. How I usually prepare my priming sugar is to place this sugar in a glass with about 3 ounces of water, boil in the microwave for 2 minutes, then let it cool and add this to my bottling bucket and prime in bulk. I do not recommend priming each bottle individually, that would be a pain and can be inconsistent. I also do not recommend varying the priming sugar based on recipe or style. Keep it simple. No need for underwhelming or overwhelming carbonation in any style in my opinion. The amounts I’ve specified will give you moderate carbonation every time, as long as your SG is stable, etc.

Cheers!