2017 Wines - Chapter 9 - Guava

I have a love-hate relationship with this fruit when it comes to wine. The first batch of wine I ever made was guava and purely by accident it was delightful. Then a couple of years ago I made a strawberry guava wine which I cold-soaked. Though the color is nice, too much time on the seeds left it bitter. I've been saving guava for a couple of years now, ready to try again. I'm pretentiously calling this one Psidium Sauvignon. Ingredients:

• 18.5# guava, mostly strawberry, some lemon and purple
• 46oz Sauvignon Blanc concentrate
• 1720g sugar
• 8.5 quarts water
• 6t pectic enzyme
• 0.5g Lallzyme EX
• 1t Fermaid K step fed
• 1t GoFerm
• 10g citric acid
• 10g tartaric acid
• 5g bentonite in primary
• 6g Opti White
• 3g Booster Blanc

I simmered the guava and assembled the wine. This was my first chance to use the new temperature control system. QA 23 was the yeast, and the lower limit was 15C/59F so I set it there and off she went.

The temp was very steady around 15C/59F. It oscillated a little bit but I tweaked some setting and by the end it was very stable. It didn't slow the ferment very much however and it still ripped through in about 7 days.

Wine Temp Control System: Update 1

I kicked off guava wine this weekend and it gave me an opportunity to test the Arduino temperature control system Adam and I built.

I acknowledge this is completely over-engineered. Let us have our fun, OK?

I secured the pump under the spigot.

I ran the thermometer through the hole in the lid and directly into the wine.

And this is probably the cause of my temperature fluctuations. I'm set at 15c/59F, the lower tolerance of my qa23 yeast. The Fi hangs around too long and overdrives the Fp, all of which means it continues to heat for a little while when it should have switched back to cooling.

The fluctuations seem to be getting smaller so I'm going to let it ride and see.

Wine Temp Control System

I have struggled for some time to control temperatures during fermentation. Cooling whites and warming reds is a challenge for home winemakers. So I read with interest a forum post in which a home winemaker attempted a solution to this problem. I talked it over with Adam who designed a solution, and over Christmas break we got to work.

The first version of the device proved under-powered. This post will detail the second version. The materials:

• Arduino Microcontroller
• Power supply cable
• Temp sensor
• Motor drivers (3)
• 5V regulator
• Relay boards (2)
• Terminal blocks (3)
• 500W power supply
• 3-fan Peltier cooling device
• Wire, solder, tools

The basic layout of this is 120VAC to 12V DC power, which for the purposes of the relays and the Arduino gets regulated down to 5V DC with the regulator. The three terminal blocks are 12V, 5V, and  a common ground. The fans and the pump run through the relays, but in this version they stay on all the time, with the relays only opening when the program is refreshed and uploaded. The Arduino controller sets the direction and voltage to the Peltier coolers through the 12V motor drivers.

We are using a PID controller. We had to adjust some code and do some "loop tuning" but now it seems very stable.

The next steps are to add power (so that it runs without the computer), add the LCD, and build a container.

Cooling Off (the wine, silly)

I've been thinking about ways to keep my white wine fermentations cool and slow. So far my solution has been to put the fermentation bucket in a tub, fill the tub with water, and drop ice packs in the water to keep it cool. The temps (and resulting wine) have been variable.

A thread by Sean on the WMT wine forum prompted me to get moving on this. I will need the help of my engineer son Adam. We started spec'ing it out today. We'll use a different model than Sean did. He pumped the wine itself through the cooler. I plan on only pumping the tub water through the cooler, using the water as a coolant.

I'm trying hard to contribute. I had never heard of peltier coolers, but after doing some research I found one on Amazon that seems to meet Adam's requirements. In response Adam texted,

"I checked out the specs on that TEC, it's max current is 15A but it has the various DT curves down to 3A. If we design the control loop right I bet we can get away with a 3-6A current."

Right.

Anyway, we're tentatively planning to use an Arduino unit as the controller. I'd never heard of that either until today. Stay tuned.

In the meantime today we smoked some salmon for dinner.