Bench Trial

A winemaker does their experimental lab work on a lab table; historically, winemakers used a bench beside their fermenters. Those tests have become known as bench trials. The purpose of a bench trial is to test various combinations and quantities of additions to determine the best one.

Test and Control Flasks

Addition (front flask) diluted in a scaled-down fashion as described below

There are various steps required to complete a bench trial.

We first take a larger sample from each test batch, divide up into smaller equal amounts. For example, if I want to trial a bit of a specific addition, I would take 500 mL of juice from Batch 2 and divide into 5-100 mL flasks,
I will add progressively larger amounts of the addition to each flask on a scaled-down basis; for example, these test flasks will receive (scaled down), 10.0 to 20.0 g/HL, in increments of 2.5 g.
Sensory Analysis: See below. I can determine what the final addition amount that will give the appropriate result. This particular amendment provides astringency and a little body to wine. We do this analysis blind. In other words, neither I nor my taste tester will know which analysis cup has which addition amount.
Colour: Although the the amendment to stabilize colour will not fully develop for months, it will give me a guideline to follow. The amendment combines with colour molecules called anthocyanins to stabilize them and make them less prone to breaking apart. If the colour molecules break apart, we will turn our wine from a nice deep desirable red to a less pleasing washed out red. The goal of colour retention in Haskap is particularly important, as consumers expect and believe a more highly coloured wine is of higher quality (this theory has been proven again and again in taste tests). By its very nature, Haskap juice does exhibit an intense colour, and we want the wine to reflect this potential.

What do I mean by scale-up and scale-down?

Scaling-up: is an increase according to a fixed ratio. It can be described this way - if I have 1000 L, and the instructions say ‘add 10-20 g of the amendment per HL, I would add 100 g to 200 g per 1000 L since 1000 L is 10 times 1 HL. (1 HL or hectoliter is 100 liters).

Scaling-down: is a laboratory method of adding test variables to a rather minuscule amount of wine on a ratio basis. I’m working with really small amounts and I have to do a little math. Plus, in order to do a scaled-down addition with the amounts being so small, I also have to mix the measured amendment with a larger amount with water and pipette out a mathematically determined amount, because I don’t have the means to weigh such a small quantity (I’m talking fraction of a milligram, which itself is 1000th of a gram).

The math would be calculated like this:

Instructions: add 10-20 g per HL.

Amount per 100 mL is incredibly small as you convert grams to mg. I therefore need 10 mg in 100 mL. 10 mg is an amount that is difficult to accurately measure by itself. In order to compensate for that difficulty, I mix a larger amount with a some water and figure out how much is in it. Knowing I can weigh out a gram (1000 mg), and add it to 100 mL of water, I can finish with 10 mg in each mL mixed solution. I have pipettes that can pipette down in increments as small as 0.10 mL, so doing the following task is not impossible.

I’ll be putting progressively larger amounts of the amendment/water mixture in each flask. Remember I have 10 mg in each mL of mixed solution.

Flask 1: the control has no additions

Flask 2: 10 mg or 1 mL of the mixed water and amendment solution

Flask 3: 12.5 mg or 1.25 mL “ “

Flask 4: 15 mg or 1.5 mL ‘‘ ‘‘

Flask 5: 17.5 mg or 1.75 mL “ “

Flask 6: 20 mg or 2.0 mL “ “

Step 3: Sensory Analysis (including colour, aroma, taste, mouthfeel, body); a pretty good baseline for starting our additions should be obtainable. First we compare A to B. Rinse mouth, and compare the ‘winner’ of A and B to C. Repeat down the line. The current comparison is for mouthfeel (including body and astringency) and colour. Ideally, we would have taste-testers but in this current environment, we have to rely on our own perceptions. Both of us agreed that the lower addition rate of 10 g/HL had the most promising result, so we added that to the test batches yesterday.

Pouring the Tasting Cups

These are randomly labeled for blind sensory analysis

Bench Trials in Winemaking

Bench Trial